Resin composition for underlayer film formation, layered product, method for forming pattern, imprint forming kit and process for producing device

ABSTRACT

Provided are a resin composition for underlayer film formation with which a variation hardly occurs in the line width distribution after processing due to a small thickness of a residual film after mold pressing, a layered product, a method for forming a pattern, an imprint forming kit, and a process for producing a device. 
     A resin composition for underlayer film formation includes a resin having a group represented by General Formula (A) and at least one group selected from a group represented by General Formula (B), an oxiranyl group and an oxetanyl group, a nonionic surfactant and a solvent. R a1  represents a hydrogen atom or a methyl group, R b1  and R b2  each independently represent a group selected from an unsubstituted linear or branched alkyl group having 1 to 20 carbon atoms and an unsubstituted cycloalkyl group having 3 to 20 carbon atoms, R b3  represents a group selected from an unsubstituted linear or branched alkyl group having 2 to 20 carbon atoms and an unsubstituted cycloalkyl group having 3 to 20 carbon atoms, and R b2  and R b3  may be bonded to each other to form a ring.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of PCT International Application No.PCT/JP2015/073292 filed on Aug. 20, 2015, which claims priority under 35U.S.C § 119(a) to Japanese Patent Application No. 2014-168721 filed onAug. 21, 2014. Each of the above application(s) is hereby expresslyincorporated by reference, in its entirety, into the present application

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a resin composition for underlayer filmformation, a layered product, a method for forming a pattern, a kit, anda process for producing a device. More specifically, the presentinvention relates to a resin composition for underlayer film formationwhich is used for improving adhesiveness between a photocurablecomposition for imprints and a base material. More particularly, thepresent invention relates to a resin composition for underlayer filmformation which is used for patterning through photoirradiation, andwhich is used in manufacturing of semiconductor integrated circuits,flat screens, microelectromechanical systems (MEMS), sensor devices,optical discs, magnetic recording media such as high-density memorydisks, optical members such as diffraction gratings and reliefholograms, optical films or polarizing elements for production ofnanodevices, optical devices, and flat panel displays, thin-filmtransistors in liquid-crystal displays, organic transistors, colorfilters, overcoat layers, pillar materials, rib materials for liquidcrystal alignment, microlens arrays, immunoassay chips, DNA separationchips, microreactors, nanobio devices, optical waveguides, opticalfilters, photonic liquid crystals, and molds for imprints.

2. Description of the Related Art

Imprint technology is a development advanced from embossing technologywell known in the art of optical disc production, which includespressing a mold prototype with a concave-convex pattern formed on itssurface (this is generally referred to as “mold”, “stamper” or“template”) against a resist to thereby accurately transfer a finepattern onto the resist through mechanical deformation of the resist. Inthis technology, when a mold is prepared once, microstructures such asnanostructures can then be easily and repeatedly molded, and therefore,this is economical, and in addition, harmful wastes and discharges fromthis nanotechnology are reduced. Accordingly, in recent years, it hasbeen anticipated that this will be applied to various technical fields.

Two methods of imprint technology have been proposed; one is a thermalimprint method using a thermoplastic resin as the material to be worked(for example, see S. Chou et al.: Appl. Phys. Lett. Vol. 67,3114(1995)), and the other is an imprint method using a curablecomposition (for example, see M. Colbun et al: Proc. SPIE, Vol. 3676,379 (1999)). In the thermal imprint method, a mold is pressed against athermoplastic resin heated up to a temperature not lower than the glasstransition temperature thereof, then the thermoplastic resin is cooledto a temperature not higher than the glass transition temperaturethereof and thereafter the mold is released to thereby transfer themicrostructure of the mold onto the resin on a substrate. This method isvery simple and convenient, and is also applicable to a variety of resinmaterials and glass materials.

On the other hand, imprinting is a method of transferring a fine patternonto a photo-cured material, by allowing a curable composition tophoto-cure under photoirradiation through a light transmissive mold or alight transmissive substrate, and then separating the mold. This methodis applicable to the field of high-precision processing for formingultrafine patterns such as fabrication of semiconductor integratedcircuits, since the imprinting may be implemented at room temperature.In recent years, new trends in development of nano-casting based on acombination of advantages of both, and reversal imprinting capable ofcreating a three-dimensional laminated structure have been reported.

In such an imprint method, the following applications have beenproposed.

A first application relates to a geometry (pattern) itself obtained bymolding being functionalized so as to be used as a nanotechnologycomponent, or a structural member, examples of which include a varietyof micro- or nano-optical components, high-density recording media,optical films, and structural members of flat panel displays.

A second application relates to the building-up of a laminated structureby simultaneous casting of microstructures and nanostructures or bysimple layer-to-layer alignment, and use of the laminated structure formanufacturing a Micro-Total Analysis System (μ-TAS) or a biochip.

A third application relates to use of the thus-formed pattern as a maskthrough which a substrate is processed by a method such as etching. Byvirtue of high precision alignment and a high degree of integration,this technique can replace a conventional lithographic technique infabrication of high-density semiconductor integrated circuits,fabrication of transistors in liquid crystal displays, and magneticprocessing for next-generation hard disks referred to as patternedmedia. Efforts to use imprinting practically in these applications haverecently become active.

With progress of activities in imprinting, adhesiveness between thesubstrate and the photocurable composition for imprints has come to be aproblem. In imprinting, the photocurable composition for imprints isapplied over the surface of the substrate, the photocurable compositionfor imprints is allowed to cure under photoirradiation, in a state ofthe surface of the substrate being in contact with a mold, and then themold is separated. In the step of separating the mold, there may be acase where the cured product is separated from the substrate andunfortunately adheres to the mold. This is thought to be because theadhesiveness between the substrate and the cured material is lower thanthe adhesiveness between the mold and the cured material. As a solutionto the foregoing problem, a resin composition for underlayer filmformation for improving the adhesiveness between the substrate and thecured material has been studied (JP2009-503139A, JP2013-093552A, andJP2014-024322A).

SUMMARY OF THE INVENTION

However, in a case where imprinting is carried out using a resincomposition for underlayer film formation so far, it has been found thatthere is a tendency that a variation in the thickness distribution of aresidual film layer derived from the resin composition for underlayerfilm formation is large. When a variation in the thickness distributionof a residual film layer is large, there was a case where a variationoccurs in the line width distribution after etching.

Accordingly, an object of the present invention is to provide a resincomposition for underlayer film formation with which a variation hardlyoccurs in the line width distribution after processing due to a smallvariation in the thickness distribution of a residual film layer aftermold pressing, a layered product, a method for forming a pattern, animprint forming kit, and a process for producing a device.

As a result of extensive studies, the present inventors have found thatthe above-mentioned object can be achieved by incorporating a nonionicsurfactant into a resin composition for underlayer film formation. Thepresent invention has been completed based on such a finding. Thepresent invention provides the following.

<1-0> A resin composition for underlayer film formation, comprising:

a resin having a group represented by General Formula (A) and at leastone group selected from a group represented by General Formula (B¹), anoxiranyl group and an oxetanyl group;

a nonionic surfactant; and

a solvent:

in General Formulae (A) and (B¹), the wavy line represents a positionconnected to the main chain or side chain of the resin,

R^(a1) represents a hydrogen atom or a methyl group, and

R^(b11), R^(b12), and R^(b13) each independently represent a groupselected from an unsubstituted linear or branched alkyl group having 1to 20 carbon atoms and an unsubstituted cycloalkyl group having 3 to 20carbon atoms, and two of R^(b11), R^(b12), and R^(b13) may be bonded toeach other to form a ring.

<1> A resin composition for underlayer film formation, comprising:

a resin having a group represented by General Formula (A) and at leastone group selected from a group represented by General Formula (B), anoxiranyl group and an oxetanyl group;

a nonionic surfactant; and

a solvent:

in General Formulae (A) and (B), the wavy line represents a positionconnected to the main chain or side chain of the resin,

R^(a1) represents a hydrogen atom or a methyl group, and

R^(b1) and R^(b2) each independently represent a group selected from anunsubstituted linear or branched alkyl group having 1 to 20 carbon atomsand an unsubstituted cycloalkyl group having 3 to 20 carbon atoms,

R^(b3) represents a group selected from an unsubstituted linear orbranched alkyl group having 2 to 20 carbon atoms and an unsubstitutedcycloalkyl group having 3 to 20 carbon atoms, and

R^(b2) and R^(b3) may be bonded to each other to form a ring.

<2> The resin composition for underlayer film formation according to<1>, comprising 0.01 to 25 parts by mass of the nonionic surfactant withrespect to 100 parts by mass of the resin.

<3> The resin composition for underlayer film formation according to <1>or <2>, in which, in General Formula (B), at least one of R^(b1),R^(b2), and R^(b3) is a cycloalkyl group having 3 to 20 carbon atoms, orR^(b2) and R^(b3) are bonded to each other to form a ring.

<4> The resin composition for underlayer film formation according to anyone of <1> to <3>, in which the resin has at least one repeating unitselected from the following General Formulae (II) to (IV):

in General Formulae (II) to (IV), R²¹ and R³¹ each independentlyrepresent a hydrogen atom or a methyl group,

R²², R²³, R³², R³³, R⁴², and R⁴³ each independently represent a groupselected from an unsubstituted linear or branched alkyl group having 1to 20 carbon atoms and an unsubstituted cycloalkyl group having 3 to 20carbon atoms,

R²⁴, R³⁴, and R⁴⁴ each independently represent a group selected from anunsubstituted linear or branched alkyl group having 2 to 20 carbon atomsand an unsubstituted cycloalkyl group having 3 to 20 carbon atoms,

R²³ and R²⁴, R³³ and R³⁴, and R⁴³ and R⁴⁴ may be bonded to each other toform a ring, and

L³ and L⁴ each independently represent a divalent linking group.

<5> The resin composition for underlayer film formation according to anyone of <1> to <4>, in which the resin has a repeating unit representedby General Formula (I) and at least one of a repeating unit representedby General Formula (II) and a repeating unit represented by GeneralFormula (III), and has a mass-average molecular weight of 5,000 to50,000:

in General Formulae (I) to (III), R¹¹, R¹², R²¹, and R³¹ eachindependently represent a hydrogen atom or a methyl group,

R²², R²³, R³², and R³³ each independently represent a group selectedfrom an unsubstituted linear or branched alkyl group having 1 to 20carbon atoms and an unsubstituted cycloalkyl group having 3 to 20 carbonatoms,

R²⁴ and R³⁴ each independently represent a group selected from anunsubstituted linear or branched alkyl group having 2 to 20 carbon atomsand an unsubstituted cycloalkyl group having 3 to 20 carbon atoms, and

R²³ and R²⁴, and R³³ and R³⁴ may be bonded to each other to form a ring,and

L¹ and L³ each independently represent a divalent linking group.

<6> The resin composition for underlayer film formation according to<5>, in which the resin contains a repeating unit selected from arepeating unit where, in General Formula (II), at least one of R²², R²³,or R²⁴ is a cycloalkyl group having 3 to 20 carbon atoms, or R²³ and R²⁴are bonded to each other to form a ring, and a repeating unit where, inGeneral Formula (III), at least one of R³², R³³, or R³⁴ is a cycloalkylgroup having 3 to 20 carbon atoms, or R³³ and R³⁴ are bonded to eachother to form a ring.

<7> The resin composition for underlayer film formation according to <5>or <6>, in which the resin has a molar ratio of repeating unitsrepresented by General Formula (I): a total of repeating unitsrepresented by General Formula (II) and repeating units represented byGeneral Formula (III) of 5:95 to 95:5.

<8> The resin composition for underlayer film formation according to <1>or <2>, in which the resin has a repeating unit having a grouprepresented by General Formula (A), and a repeating unit having at leastone group selected from an oxiranyl group and an oxetanyl group.

<9> The resin composition for underlayer film formation according to<8>, in which the resin has a molar ratio of the repeating unit having agroup represented by General Formula (A):the repeating unit having atleast one group selected from an oxiranyl group and an oxetanyl group of10:90 to 97:3.

<10> The resin composition for underlayer film formation according to<8> or <9>, in which the resin has at least one repeating unit selectedfrom the following General Formulae (1) to (3) and at least onerepeating unit selected from the following General Formulae (4) to (6):

in General Formulae (1) to (6), R¹¹¹, R¹¹², R¹²¹, R¹²², R¹³¹, R¹³²,R¹⁴¹, R¹⁵¹ and R¹⁶¹ each independently represent a hydrogen atom or amethyl group,

L¹¹⁰, L¹²⁰, L¹³⁰, L¹⁴⁰, L¹⁵⁰ and L¹⁶⁰ each independently represent asingle bond or a divalent linking group, and

T represents any one of the groups represented by General Formulae(T-1), (T-2) and (T-3);

in General Formulae (T-1) to (T-3), R^(T1) and R^(T3) each independentlyrepresent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms,

represents 0 or 1,

q represents 0 or 1,

n represents an integer of 0 to 2, and

a wavy line represents a position connected to L¹⁴⁰, L¹⁵⁰ or L¹⁶⁰.

<11> The resin composition for underlayer film formation according to<10>, in which T is a group represented by General Formula (T-1).

<12> The resin composition for underlayer film formation according toany one of <1> to <11>, in which the solvent is propylene glycolmonomethyl ether acetate.

<13> The resin composition for underlayer film formation according toany one of <1> to <12>, further comprising at least one of an acid or athermal acid generator.

<14> The resin composition for underlayer film formation according toany one of <1> to <13>, in which the content of the solvent is 95 to99.9 mass %.

<15> The resin composition for underlayer film formation according toany one of <1> to <14>, in which the contact angle of the film formed ofthe resin composition for underlayer film formation with respect towater is 50° or more, and the contact angle of the film with respect todiiodomethane is 30° or more.

<16> The resin composition for underlayer film formation according toany one of <1> to <15>, which is used for the formation of an underlayerfilm for imprints.

<17> A layered product having an underlayer film obtained by curing theresin composition for underlayer film formation according to any one of<1> to <16> on the surface of a base material.

<18> A method for forming a pattern, comprising:

applying the resin composition for underlayer film formation accordingto any one of <1> to <16> onto the surface of a base material in theform of layer;

heating the applied resin composition for underlayer film formation toform an underlayer film;

applying a photocurable composition onto a surface of the underlayerfilm in the form of layer;

pressing a mold having a pattern on the photocurable composition;

curing the photocurable composition by photoirradiation in a state ofthe mold being pressed; and

separating the mold.

<19> The method for forming a pattern according to <18>, in which theheating temperature is 120° C. to 250° C. and the heating time is 30seconds to 10 minutes, in the forming an underlayer film.

<20> An imprint forming kit having the resin composition for underlayerfilm formation according to any one of <1> to <16> and a photocurablecomposition.

<21> The imprint forming kit according to <20>, in which the contactangle of a photocurable composition with respect to the surface of thefilm formed of the resin composition for underlayer film formation is10° or more.

<22> A process for producing a device, comprising the method for forminga pattern according to <18> or <19>.

According to the present invention, it has now become possible toprovide a resin composition for underlayer film formation with which avariation hardly occurs in the line width distribution after processingdue to a small variation in the thickness distribution of a residualfilm layer after mold pressing, a layered product, a method for forminga pattern, a kit, and a process for producing a device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a manufacturing process in a case wherea photocurable composition for imprints is used for processing of a basematerial by etching.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The contents of the present invention are described in detailhereinunder.

As used herein, the numerical value ranges shown with “to” means rangesincluding the numerical values indicated before and after “to” as theminimum and maximum values, respectively.

As used herein, the term “(meth)acrylate” refers to acrylate andmethacrylate; “(meth)acrylic” refers to acrylic and methacrylic; and“(meth)acryloyl” refers to acryloyl and methacryloyl.

As used herein, the term “imprint” is preferably meant to indicatepattern transfer in a size of 1 nm to 10 mm and more preferably meant toindicate pattern transfer in a size of about 10 nm to 100 μm(nanoimprint).

Regarding the expression of “group (atomic group)” as used herein, theexpression with no indication of “substituted” or “unsubstituted”includes both “substituted group” and “unsubstituted group”. Forexample, “alkyl group” includes not only an alkyl group not having asubstituent (unsubstituted alkyl group) but also an alkyl group having asubstituent (substituted alkyl group).

As used herein, the term “light” includes not only those in thewavelength regions of ultraviolet, near-ultraviolet, far ultraviolet,visible light and infrared, and other electromagnetic waves, but alsoradiation rays. The radiation rays include microwaves, electron beams,EUV and X-rays. Laser light such as 248 nm excimer laser, 193 nm excimerlaser, and 172 nm excimer laser may also be used. These sorts of lightmay be monochromatic light (single wavelength light) which have passedthrough an optical filter, or light that includes a plurality ofdifferent wavelengths (complex light).

Unless otherwise specified, the mass-average molecular weight and thenumber-average molecular weight in the present invention refer to thoseas measured by gel permeation chromatography (GPC). For GPC, withrespect to the obtained polymer, the solvent is removed to isolate thepolymer and the resulting solids are diluted with tetrahydrofuran to 0.1mass %. In the GPC, the measurement is carried out by using HLC-8020GPC(manufactured by Tosoh Corporation), with three columns of TSKgel SuperMultipore HZ-H (manufactured by Tosoh Corporation, 4.6 mmID×15 cm)connected in series as columns. The measurement was carried out using anRI detector under the conditions of a sample concentration of 0.35 mass%, a flow rate of 0.35 mL/min, a sample injection volume of 10 μL, and ameasurement temperature of 40° C.

As used herein, the term “total solid content” refers to a total mass ofcomponent(s) remaining when a solvent is excluded from the entirecomposition.

The “solid content” in the present specification is a solid content at25° C.

The resin composition for underlayer film formation according to thepresent invention contains a resin having a group represented by GeneralFormula (A) and at least one group selected from a group represented byGeneral Formula (B¹), an oxiranyl group and an oxetanyl group, anonionic surfactant, and a solvent.

In a case where a conventional resin composition for underlayer filmformation is used, it was found that there is a tendency that avariation in the thickness distribution of a residual film layer islarge.

As used herein, the term “residual film layer” refers to a layercorresponding to the thickness between the pattern bottom and thesubstrate surface. This residual film layer becomes an unnecessary layerin a case of transferring a pattern to a substrate by post-processingsuch as dry etching after patterning. Therefore, when a substrate isetched, it is necessary to first remove a residual film layer. When theresidual film layer is removed by dry etching, the pattern portion isalso damaged and so it is necessary to reduce the thickness of theresidual film layer. In nanoimprinting, a resist for nanoimprints(imprint layer) flows into the pattern of a mold according to thepattern arrangement to thereby carry out pattern formation. Depending onthe pattern distribution and also in a case where the resist coatingmethod is carried out by an inkjet method, patterning is carried out insuch a manner that due to wet spreading of a resist liquid betweenlanding positions of resist droplets, the resist liquid flows onto aresidual film layer and then the resist wet-spreads within a desiredpattern area. Inside the residual film layer, there is viscosityresistance due to the interaction between the resins at the interfacebetween the underlayer film surface and the resist liquid, so thefluidity is decreased. The influence of lowering of fluidity due toviscosity resistance is increased as the thickness of the residual filmlayer becomes smaller. Therefore, in a region where the residual filmlayer thickness is small, the fluidity of the resist liquid is incapableof being sufficiently maintained and wetting spreading becomes poor,which has then resulted in a variation in the thickness distribution ofthe residual film layer.

According to the resin composition for underlayer film formationaccording to the present invention, it has now become possible toprovide a resin composition for underlayer film formation with which avariation hardly occurs in the line width distribution after processingdue to that incorporation of a nonionic surfactant leads to a reducedvariation in the thickness distribution of a residual film layer aftermold pressing.

The mechanism by which the above-mentioned effect is achieved ispresumed to be due to the following. In other words, it is consideredthat incorporation of a nonionic surfactant into a resin composition forunderlayer film formation results in lowering of surface tension of theresin composition for underlayer film formation, thus improvingcoatability, and consequently surface roughness can be reduced, wherebyit is possible to form an underlayer film having excellent surfaceflatness. It is considered that the improvement in surface flatness canlead to more smooth flow of the resist during imprinting andconsequently it has become possible to reduce the residual filmthickness distribution. Further, it is considered that since water andoil repellency of the underlayer film is improved, excessive spreadingof a photocurable composition applied onto the underlayer film surfacecan be suppressed, and therefore, at the time of application of thephotocurable composition by an inkjet method, controllability of landingpositions of droplets can be improved and the resist arrangement indesired distribution corresponding to the pattern arrangement can becarried out with high accuracy, which can then result in improveduniformity of a residual film thickness after patterning by animprinting method. Further, it is considered that since theincorporation of a nonionic surfactant leads to a decrease in theinteraction between the surface of an underlayer film formed by a resincomposition for underlayer film formation and the photocurablecomposition, thereby reducing viscosity resistance, fluidity of a resistliquid is improved in formation of an imprint layer by pressing a moldhaving a pattern, correspondingly the thickness of the residual filmlayer on the base material surface is decreased, and the thicknessdistribution can also be further reduced. Further, since the thicknessdistribution of the residual film layer of the underlayer film on thebase material surface can be further reduced, a base material can besubstantially uniformly processed in a case of processing such a basematerial by a method such as etching, and therefore a variation in theline width distribution after processing can hardly occur.

Further, according to the resin composition for underlayer filmformation according to the present invention, incorporation of anonionic surfactant may also improve the releasability between the moldand the imprint layer during mold separation. The mechanism by which theabove-mentioned effect is achieved is presumed to be due to that anonionic surfactant transfers from the underlayer film side to theimprint layer side during flow of the resist liquid and also adheres toan interface between the mold and the imprint layer, wherebyreleasability between the mold and the imprint layer is improved.

Further, in the resin composition for underlayer film formationaccording to the present invention, since the resin has a grouprepresented by General Formula (A), it is also possible to improveadhesiveness between the underlayer film and the imprint layer.

Further, since the group represented by General Formula (B¹) is acarboxyl group protected with a tertiary carbon and undergoes adeprotection reaction by an acid and/or heating, thus producing acarboxyl group, in a case where the resin has a group represented byGeneral Formula (B¹), it is possible to improve adhesiveness with thebase material or the imprint layer. Furthermore, the resin having acarboxyl group protected with a tertiary carbon exhibits a weakinteraction between polymer chains, and can therefore suppress anincrease of viscosity due to solvent drying and can also improve surfaceflatness, in a step of drying a solvent after application is completed.

Further, in a case where the resin has a group selected from an oxiranylgroup and an oxetanyl group, shrinkage at the time of thermal curing issuppressed and therefore cracking or the like of the underlayer filmsurface is suppressed, whereby surface flatness can also be improved.

The resin composition for underlayer film formation according to thepresent invention can be preferably used in the formation of anunderlayer film for imprints.

Hereinafter, individual components of the resin composition forunderlayer film formation according to the present invention will bedescribed.

<<Resin>>

In the resin composition for underlayer film formation according to thepresent invention, the resin has a group represented by General Formula(A) and at least one group selected from a group represented by GeneralFormula (B¹), an oxiranyl group and an oxetanyl group.

In General Formulae (A) and (B¹), the wavy line represents a positionconnected to the main chain or side chain of the resin,

R^(a1) represents a hydrogen atom or a methyl group, and

R^(b11), R^(b12), and R^(b13) each independently represent a groupselected from an unsubstituted linear or branched alkyl group having 1to 20 carbon atoms and an unsubstituted cycloalkyl group having 3 to 20carbon atoms, and two of R^(b11), R¹², and R^(b13) may be bonded to eachother to form a ring.

R^(b11), R^(b12), and R^(b13) each independently represent a groupselected from an unsubstituted linear or branched alkyl group having 1to 20 carbon atoms and an unsubstituted cycloalkyl group having 3 to 10carbon atoms.

The number of carbon atoms in the unsubstituted linear alkyl group ispreferably 1 to 20, more preferably 1 to 15, and still more preferably 1to 10. Specific examples of the unsubstituted linear alkyl group includea methyl group, an ethyl group, a propyl group, a hexyl group, and anoctyl group.

The number of carbon atoms in the unsubstituted branched alkyl group ispreferably 3 to 20, more preferably 3 to 15, and still more preferably 3to 10. Specific examples of the unsubstituted branched alkyl groupinclude an iso-propyl group, an n-butyl group, a sec-butyl group, atert-butyl group, and an iso-butyl group.

The number of carbon atoms in the unsubstituted cycloalkyl group ispreferably 3 to 20, more preferably 3 to 15, and still more preferably 3to 10. The cycloalkyl group may be monocyclic or polycyclic. Specificexamples of the unsubstituted cycloalkyl group include a cyclopropylgroup, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, anorbornyl group, an isobornyl group, a camphanyl group, an adamantylgroup, a dicyclopentyl group, an α-pinenyl group, and a tricyclodecanylgroup.

Two of R^(b11), R^(b12), and R^(b13) may be bonded to each other to forma ring. Examples of the ring formed by bonding of two of R^(b11),R^(b12), and R^(b13) to each other include a cyclopentane ring, acyclohexane ring, a norbornane ring, an isobornane ring, and anadamantane ring.

Further, it is not preferable to form a ring by bonding of R^(b11),R^(b12), and R^(b13) to one another. This is because the deprotectionreaction of a tertiary ester by an acid and/or heating hardly proceedssince carbocations at the bridgehead position are not stable. Examplesof the group not preferable as —C(R^(b11))(R^(b12))(R^(b13)) include a1-adamantyl group, a norborn-1-yl group, and an isoborn-1-yl group.

In the resin composition for underlayer film formation according to thepresent invention, the resin preferably has a group represented byGeneral Formula (A) and at least one group selected from a grouprepresented by General Formula (B), an oxiranyl group and an oxetanylgroup. Hereinafter, an oxiranyl group and an oxetanyl group are alsoreferred to as a cyclic ether group.

In the present invention, a preferred embodiment of the resin is a resinhaving a group represented by General Formula (A) and a grouprepresented by General Formula (B) (a resin of the first aspect), or aresin having a group represented by General Formula (A) and a cyclicether group (a resin of the second aspect). The resin of the firstaspect and the resin of the second aspect may be used alone or incombination of both.

In General Formulae (A) and (B), the wavy line represents a positionconnected to the main chain or side chain of the resin,

R^(a1) represents a hydrogen atom or a methyl group, and

R^(b1) and R^(b2) each independently represent a group selected from anunsubstituted linear or branched alkyl group having 1 to 20 carbon atomsand an unsubstituted cycloalkyl group having 3 to 20 carbon atoms,R^(b3) represents a group selected from an unsubstituted linear orbranched alkyl group having 2 to 20 carbon atoms and an unsubstitutedcycloalkyl group having 3 to 20 carbon atoms, and R^(b2) and R^(b3) maybe bonded to each other to form a ring.

R^(b1) and R^(b2) each independently represent a group selected from anunsubstituted linear or branched alkyl group having 1 to 20 carbon atomsand an unsubstituted cycloalkyl group having 3 to 20 carbon atoms.

R^(b1) and R^(b2) have the same definition as in R^(b11) and R^(b12) ofthe above-mentioned Formula (B¹), and preferred ranges thereof are alsothe same.

R^(b3) represents a group selected from an unsubstituted linear orbranched alkyl group having 2 to 20 carbon atoms and an unsubstitutedcycloalkyl group having 3 to 20 carbon atoms.

The number of carbon atoms in the unsubstituted linear alkyl group ispreferably 2 to 20, more preferably 2 to 15, and still more preferably 2to 10. Specific examples of the unsubstituted linear alkyl group includean ethyl group, a propyl group, a hexyl group, and an octyl group.

The unsubstituted branched alkyl group and the unsubstituted cycloalkylgroup have the same definition as in R^(b13) of the above-mentionedformula (B¹), and preferred ranges thereof are also the same.

Examples of the ring formed by bonding of R^(b2) and R^(b3) to eachother include a cyclopentane ring, a cyclohexane ring, a norbornanering, an isobornane ring, and an adamantane ring.

The resin of the first aspect has a group represented by General Formula(B). The group represented by General Formula (B) is more readilysusceptible to the deprotection reaction of a tertiary ester by an acidand/or heating, due to carbocation intermediates in the deprotectionreaction, or low energy of the transition state of the reaction.Therefore, it is easy to form an underlayer film having a high adhesiveforce to an imprint layer and a substrate.

The resin of the second aspect has a cyclic ether group selected from anoxiranyl group and an oxetanyl group. Since the cyclization reaction ofthe cyclic ether group can suppress volume shrinkage due to curing, itis possible to suppress shrinkage of an underlayer film during thermalcuring, so cracking or the like of the underlayer film surface can besuppressed to thereby improve surface flatness.

In General Formula (B), it is preferred that at least one of R^(b1),R^(b2), or R^(b3) is a cycloalkyl group having 3 to 20 carbon atoms, orR^(b2) and R^(b3) are bonded to each other to form a ring. According tothis aspect, since the carbocation is likely to exist more stably, thedeprotection reaction of a tertiary ester is more likely to proceed byan acid and/or heating.

<<<Resin having group represented by General Formula (A) and grouprepresented by General Formula (B) (resin of first aspect)>>>

In the present invention, the resin of the first aspect has a grouprepresented by General Formula (A) and a group represented by GeneralFormula (B). The resin of the first aspect preferably has at least onerepeating unit selected from General Formulae (II) to (IV).

In General Formulae (II) to (IV), R²¹ and R³¹ each independentlyrepresent a hydrogen atom or a methyl group,

R²², R²³, R³², R³³, R⁴², and R⁴³ each independently represent a groupselected from an unsubstituted linear or branched alkyl group having 1to 20 carbon atoms and an unsubstituted cycloalkyl group having 3 to 20carbon atoms, R²⁴, R³⁴, and R⁴⁴ each independently represent a groupselected from an unsubstituted linear or branched alkyl group having 2to 20 carbon atoms and an unsubstituted cycloalkyl group having 3 to 20carbon atoms, and R²³ and R²⁴, R³³ and R³⁴, and R⁴³ and R⁴⁴ may bebonded to each other to form a ring, and

L³ and L⁴ each independently represent a divalent linking group.

R²², R²³, R³², R³³, R⁴², and R⁴³ have the same definition as in R^(b1)and R^(b2) of the above-mentioned General Formula (B), and preferredranges thereof are also the same.

R²⁴, R³⁴, and R⁴⁴ have the same definition as in R^(b3) of theabove-mentioned General Formula (B), and preferred ranges thereof arealso the same. Further, R⁴⁴ may be a group selected from anunsubstituted linear or branched alkyl group having 1 to 20 carbon atomsand an unsubstituted cycloalkyl group having 3 to 20 carbon atoms. Thatis, R⁴⁴ may be a methyl group.

L³ and L⁴ each independently represent a divalent linking group.

Examples of the divalent linking group include a linear or branchedalkylene group, a cycloalkylene group, and a group formed by combiningthese groups. These groups may contain at least one selected from anester bond, an ether bond, an amide bond, and a urethane bond.Additionally, these groups may be unsubstituted or may have asubstituent. The substituent may be a hydroxyl group or the like. In thepresent invention, it is preferred not to contain a substituent otherthan a hydroxyl group.

The number of carbon atoms in the linear alkylene group is preferably 2to 10.

The number of carbon atoms in the branched alkylene group is preferably3 to 10.

The number of carbon atoms in the cycloalkylene group is preferably 3 to10.

Specific examples of the divalent linking group include an ethylenegroup, a propylene group, a butylene group, a hexylene group, a2-hydroxy-1,3-propanediyl group, a 3-oxa-1,5-pentanediyl group, and a3,5-dioxa-1,8-octanediyl group.

In the present invention, the resin of the first aspect preferably has arepeating unit represented by General Formula (I) and at least one of arepeating unit represented by General Formula (II) or a repeating unitrepresented by General Formula (III).

By including a repeating unit represented by General Formula (I), theresin can improve adhesiveness to an imprint layer. By including atleast one of a repeating unit represented by General Formula (II) or arepeating unit represented by General Formula (III), it is possible toimprove surface flatness and adhesiveness to a base material. Further,adhesiveness to an imprint layer, adhesiveness to a base material, andflatness of an underlayer film surface are improved, whereby separationfailure is unlikely to occur. Further, by using a resin containing theabove-mentioned repeating units, it is possible to cure an underlayerfilm without using a low molecular weight crosslinking agent or thelike, and it is possible to avoid occurrence of defects due to thesublimation of a crosslinking agent at the time of curing.

In General Formulae (I) to (III), R¹¹, R¹², R²¹, and R³¹ eachindependently represent a hydrogen atom or a methyl group,

R²², R²³, R³², and R³³ each independently represent a group selectedfrom an unsubstituted linear or branched alkyl group having 1 to 20carbon atoms and an unsubstituted cycloalkyl group having 3 to 20 carbonatoms, R²⁴ and R³⁴ each independently represent a group selected from anunsubstituted linear or branched alkyl group having 2 to 20 carbon atomsand an unsubstituted cycloalkyl group having 3 to 20 carbon atoms, andR²³ and R²⁴, and R³³ and R³⁴ may be bonded to each other to form a ring,and

L¹ and L³ each independently represent a divalent linking group.

R²², R²³, R³², and R³³ have the same definition as in R^(b1) and R^(b2)of the above-mentioned General Formula (B), and preferred ranges thereofare also the same.

R²⁴ and R³⁴ have the same definition as in R^(b3) of the above-mentionedGeneral Formula (B), and preferred ranges thereof are also the same.

L¹ and L³ each independently represent a divalent linking group.

The divalent linking group has the same definition as in theabove-mentioned divalent linking group, and a preferred range thereof isalso the same.

In the present invention, the resin of the first aspect preferablycontains a repeating unit selected from a repeating unit where, inGeneral Formula (II), at least one of R²², R²³, or R²⁴ is a cycloalkylgroup having 3 to 20 carbon atoms, or R²³ and R²⁴ are bonded to eachother to form a ring, and a repeating unit where, in General Formula(III), at least one of R³², R³³, or R³⁴ is a cycloalkyl group having 3to 20 carbon atoms, or R³³ and R³⁴ are bonded to each other to form aring. According to this aspect, the deprotection reaction of a tertiaryester is more likely to proceed by an acid and/or heating, sincecarbocations are likely to exist more stably.

In the present invention, the molar ratio of repeating units representedby General Formula (I):a total of repeating units represented by GeneralFormula (II) and repeating units represented by General Formula (III) inthe resin of the first aspect is preferably 5:95 to 95:5, morepreferably 10:90 to 90:10, still more preferably 20:80 to 80:20,particularly preferably 30:70 to 70:30, and even more preferably 40:60to 60:40.

When the percentage of General Formula (I) is set to 5 mol % or more,adhesiveness to an imprint layer can be preferably improved. When thepercentage of a repeating unit selected from General Formula (II) andGeneral Formula (III) is set to 5 mol % or more, adhesiveness to a basematerial and surface flatness can be preferably improved.

In the present invention, the resin of the first aspect may contain theother repeating unit other than repeating units represented by GeneralFormulae (I) to (III). Examples of the other repeating unit include arepeating unit represented by the above-mentioned General Formula (IV).Further examples of the other repeating unit include a repeating unitdescribed in paragraphs “0022” to “0055” of JP2014-24322A, and arepeating unit represented by General Formula (V) and a repeating unitrepresented by General Formula (VI) described in paragraph “0043” of thesame JP2014-24322A.

The content of the other repeating unit is preferably 10 mol % or less,more preferably 5 mol % or less, and still more preferably 1 mol % orless, with respect to the total content of repeating units in the resin.Further, it is also possible that the other repeating unit is notcontained. In a case where the resin is composed only of repeating unitsrepresented by General Formulae (I) to (III), the above-mentionedeffects of the present invention are more significantly obtained.

Specific examples of the repeating unit represented by General Formula(I) include the following structures. It is needless to say that thepresent invention is not limited thereto. R¹¹ and R¹² each independentlyrepresent a hydrogen atom or a methyl group, preferably a methyl group.

Among the above structures, a repeating unit represented by GeneralFormula (I-1) is preferable from the viewpoint of cost.

Specific examples of the repeating unit represented by General Formula(II) include the following structures.

Among the above structures, the following repeating unit is preferablefrom the viewpoint of deprotection properties, volatility of thedeprotected product, and cost.

Specific examples of the repeating unit represented by General Formula(III) include the following structures.

Specific examples of the repeating unit represented by General Formula(IV) include the following structures.

Specific examples of the resin are shown below. In the followingspecific examples, x represents 5 to 99 mol %, and y represents 5 to 95mol %.

<<<Resin having group represented by General Formula (A) and cyclicether group (resin of second aspect)>>>

In the present invention, the resin of the second aspect has a grouprepresented by General Formula (A) and a cyclic ether group. The resinof the second aspect preferably has a repeating unit having theabove-mentioned group represented by General Formula (A) and a repeatingunit having a cyclic ether group.

The resin of the second aspect is preferably a (meth)acrylic resin. Byusing the (meth)acrylic resin, there is a tendency that removability ofetching residues is superior.

The molar ratio of a repeating unit having a group represented byGeneral Formula (A):a repeating unit having a cyclic ether group in theresin of the second aspect is preferably 10:90 to 97:3, more preferably30:70 to 95:5, and still more preferably 50:50 to 90:10. If the molarratio is within the above-specified range, it is highly significant inthat a better underlayer film can be formed even when curing at a lowtemperature.

The resin of the second aspect may contain repeating units other than agroup represented by General Formula (A) and a cyclic ether group(hereinafter, often referred to as “other repeating units”). In a caseof containing other repeating units, the ratio thereof is preferably 1to 30 mol %, and more preferably 5 to 25 mol %.

In the resin of the second aspect, the repeating unit having a grouprepresented by General Formula (A) is preferably at least one selectedfrom repeating units represented by the following General Formulae (1)to (3).

In General Formulae (1) to (3), R¹¹¹, R¹¹², R¹²¹, R¹²², R¹³¹ and R¹³²each independently represent a hydrogen atom or a methyl group, andL¹¹⁰, L¹²⁰ and L¹³⁰ each independently represent a single bond or adivalent linking group.

R¹¹¹ and R¹³¹ are more preferably a methyl group. R¹¹², R¹²¹, R¹²² andR¹³² are still more preferably a hydrogen atom.

L¹¹⁰, L¹²⁰ and L¹³⁰ each independently represent a single bond or adivalent linking group. Examples of the divalent linking group includethose described for L³ and L⁴ of General Formulae (III) and (IV) above,and a preferred range thereof is also the same. Among them, preferred isa group consisting of one or more —CH₂—, or a group consisting of acombination of one or more —CH₂— and at least one of —CH(OH)—, —O—, or—C(═O)—. The number of atoms constituting the linking chain of L¹¹⁰,L¹²⁰, and L¹³⁰ (for example, in General Formula (2), it refers to thenumber of atoms in the chain connecting between a benzene ring and anoxygen atom adjacent to L¹²⁰, and more particularly, it is 4 in acompound of (2a) to be described hereinafter) is preferably 1 to 20, andmore preferably 2 to 10.

Specific examples of the repeating unit having a group represented byGeneral Formula (A) include the following structures. It is needless tosay that the present invention is not limited thereto. R¹¹¹, R¹¹², R¹²¹,R¹²², R¹³¹ and R¹³² each independently represent a hydrogen atom or amethyl group.

Among the above structures, preferred are the following structures.

The repeating unit having a cyclic ether group is preferably at leastone selected from repeating units represented by the following GeneralFormulae (4) to (6).

In General Formulae (4) to (6), R¹⁴¹, R¹⁵¹ and R¹⁶¹ each independentlyrepresent a hydrogen atom or a methyl group, L¹⁴⁰, L¹⁵⁰ and L¹⁶⁰ eachindependently represent a single bond or a divalent linking group, and Trepresents any one of cyclic ether groups represented by GeneralFormulae (T-1), (T-2) and (T-3).

In General Formulae (T-1) to (T-3), R^(T1) and R^(T3) each independentlyrepresent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms,p represents 0 or 1, q represents 0 or 1, n represents an integer of 0to 2, and a wavy line represents a position connected to L¹⁴⁰, L¹⁵⁰ orL¹⁶⁰.

R¹⁴¹ and R¹⁶¹ are more preferably a methyl group, and R¹⁵¹ is morepreferably a hydrogen atom.

L¹⁴⁰, L¹⁵⁰ and L¹⁶⁰ each independently represent a single bond or adivalent linking group. Examples of the divalent linking group includethose described for L³ and L⁴ of General Formulae (III) and (IV) above.Among them, preferred is a group consisting of one or more —CH₂—, or agroup consisting of a combination of one or more —CH₂— and at least oneof —CH(OH)—, —O—, or —C(═O)—, more preferred is a single bond or a groupconsisting of one or more —CH₂—, and still more preferred is a groupconsisting of 1 to 3 —CH₂—. The number of atoms constituting the linkingchain of L¹⁴⁰, L¹⁵⁰, and L¹⁶⁰ is preferably 1 to 5, more preferably 1 to3, and still more preferably 1 or 2.

R^(T1) and R^(T3) each independently represent a hydrogen atom or analkyl group having 1 to 5 carbon atoms, and are preferably a hydrogenatom, a methyl group, an ethyl group or a propyl group and morepreferably a hydrogen atom, a methyl group or an ethyl group.

p represents 0 or 1 and is preferably 0.

q represents 0 or 1 and is preferably 0.

n represents an integer of 0 to 2 and is preferably 0.

The groups represented by General Formulae (T-1) to (T-3) are preferablyGeneral Formula (T-1) and General Formula (T-2), and more preferablyGeneral Formula (T-1).

Examples of the repeating unit having a cyclic ether group include thefollowing structures. It is needless to say that the present inventionis not limited thereto. R¹⁴¹, R¹⁵¹ and R¹⁶¹ each independently representa hydrogen atom or a methyl group.

Among the above structures, preferred are the following structures.

Other repeating units that may be contained in the resin are preferablyrepeating units represented by the following General Formula (7) and/orGeneral Formula (8).

In General Formulae (7) and (8), R¹⁷¹ and R¹⁸¹ each independentlyrepresent a hydrogen atom or a methyl group, L¹⁷⁰ and L¹⁸⁰ eachrepresent a single bond or a divalent linking group, Q represents anonionic hydrophilic group, and R¹⁸² represents an aliphatic grouphaving 1 to 12 carbon atoms, an alicyclic group having 3 to 12 carbonatoms, or an aromatic group having 6 to 12 carbon atoms.

R¹⁷¹ and R¹⁸¹ each represent a hydrogen atom or a methyl group, and aremore preferably a methyl group.

L¹⁷⁰ and L¹⁸⁰ each represent a single bond or a divalent linking group.Examples of the divalent linking group include those described for L³and L⁴ of General Formulae (III) and (IV) above. The number of atomsconstituting the linking chain of L¹⁷⁰ and L¹⁸⁰ is preferably 1 to 10.

Q represents a nonionic hydrophilic group. Examples of the nonionichydrophilic group include an alcoholic hydroxyl group, a phenolichydroxyl group, an ether group (preferably a polyoxyalkylene group), anamido group, an imido group, a ureido group, a urethane group, and acyano group. Among them, more preferred are an alcoholic hydroxyl group,a polyoxyalkylene group, a ureido group, and a urethane group andparticularly preferred are an alcoholic hydroxyl group and a urethanegroup.

R¹⁸² represents an aliphatic group having 1 to 12 carbon atoms, analicyclic group having 3 to 12 carbon atoms, or an aromatic group having6 to 12 carbon atoms.

Examples of the aliphatic group having 1 to 12 carbon atoms includealkyl groups having 1 to 12 carbon atoms (for example, a methyl group,an ethyl group, a propyl group, an isopropyl group, a butyl group, anisobutyl group, a t-butyl group, a pentyl group, an isopentyl group, aneopentyl group, a hexyl group, a heptyl group, an octyl group, a2-ethylhexyl group, a 3,3,5-trimethylhexyl group, an isooctyl group, anonyl group, an isononyl group, a decyl group, an isodecyl group, anundecyl group, and a dodecyl group).

Examples of the alicyclic group having 3 to 12 carbon atoms includecycloalkyl groups having 3 to 12 carbon atoms (for example, acyclopentyl group, a cyclohexyl group, a norbornyl group, an isobornylgroup, an adamantyl group, and a tricyclodecanyl group).

Examples of the aromatic group having 6 to 12 carbon atoms include aphenyl group, a naphthyl group, and a biphenyl group. Among them,preferred are a phenyl group and a naphthyl group.

The aliphatic group, the alicyclic group and the aromatic group may havea substituent, but preferably have no substituent.

The resin of the second aspect is preferably a resin containing arepeating unit represented by General Formula (1) and a repeating unitrepresented by General Formula (4), a resin containing a repeating unitrepresented by General Formula (2) and a repeating unit represented byGeneral Formula (5), or a resin containing a repeating unit representedby General Formula (3) and a repeating unit represented by GeneralFormula (6), and more preferably a resin containing a repeating unitrepresented by General Formula (1 a) and a repeating unit represented byGeneral Formula (4a), a resin containing a repeating unit represented byGeneral Formula (2a) and a repeating unit represented by General Formula(5a), or a resin containing a repeating unit represented by GeneralFormula (3a) and a repeating unit represented by General Formula (6a).

Specific examples of the resin of the second aspect are shown below. Inthe following specific examples, x represents 5 to 99 mol %, yrepresents 1 to 95 mol %, and z represents 0 to 30 mol %.

In the present invention, the mass-average molecular weight of the resinis preferably 5,000 to 50,000. The lower limit is more preferably 8,000or more, and still more preferably 10,000 or more. The upper limit ismore preferably 35,000 or less and still more preferably 25,000 or less.By setting the mass-average molecular weight to be within theabove-specified range, it is possible to ensure good film formability.

The content of the resin in the resin composition for underlayer filmformation according to the present invention is preferably 70 to 99.99mass % with respect to the total solid content of the resin compositionfor underlayer film formation. The lower limit is, for example, morepreferably 80 mass % or more, still more preferably 85 mass % or more,and particularly preferably 90 mass % or more. The upper limit is, forexample, more preferably 99.95 mass % or less, and still more preferably99.9 mass % or less.

Further, the content of the resin is preferably 0.01 to 5 mass %, morepreferably 0.05 to 4 mass %, and still more preferably 0.1 to 3 mass %,with respect to the total amount of the resin composition for underlayerfilm formation.

If the content of the resin is within the above-specified range, it iseasy to form an underlayer film having better adhesiveness and surfaceflatness.

The resins may be used alone or in combination of two or more thereof.In a case where two or more resins are used, it is preferred that thetotal amount of two or more resins is within the above-specified range.

<<Nonionic Surfactant>>

The resin composition for underlayer film formation according to thepresent invention contains a nonionic surfactant. By including anonionic surfactant, the thickness and thickness distribution of aresidual film layer after mold pressing is small, and therefore it ispossible to achieve a resin composition for underlayer film formationwhose variation in the line width distribution after processing isunlikely to occur. Furthermore, it is also possible to improve thereleasability between the mold and the imprint layer during moldseparation.

In the present invention, the nonionic surfactant is a compound havingat least one hydrophobic portion and at least one nonionic hydrophilicportion. The hydrophobic portion and the hydrophilic portion may berespectively present at the terminal of a molecule or may be presentwithin the molecule. The hydrophobic portion is formed of a hydrophobicgroup selected from a hydrocarbon group, a fluorine-containing group,and an Si-containing group, and the number of carbon atoms in thehydrophobic portion is preferably 1 to 25, more preferably 2 to 15,still more preferably 4 to 10, and most preferably 5 to 8. The nonionichydrophilic portion preferably has at least one group selected from thegroup consisting of an alcoholic hydroxyl group, a phenolic hydroxylgroup, an ether group (preferably a polyoxyalkylene group or a cyclicether group), an amido group, an imido group, a ureido group, a urethanegroup, a cyano group, a sulfonamido group, a lactone group, a lactamgroup, and a cyclocarbonate group. Among them, more preferred is analcoholic hydroxyl group, a polyoxyalkylene group or an amido group, andparticularly preferred is a polyoxyalkylene group. The nonionicsurfactant may be any nonionic surfactant of a hydrocarbon-basedsurfactant, a fluorine-based surfactant, an Si-based surfactant, or afluorine.Si-based surfactant, but it is more preferably a fluorine-basedor Si-based surfactant and still more preferably a fluorine-basedsurfactant. By using such a nonionic surfactant, it is easy to obtainthe effect described above. Further, it is capable of improving coatinguniformity, and therefore a good coating film is obtained in coatingusing a spin coater or a slit scanning coater. Here, the“fluorine.Si-based nonionic surfactant” refers to a nonionic surfactantsatisfying requirements of both a fluorine-based surfactant and anSi-based surfactant.

Further, in the present invention, the content of fluorine in thefluorine-based nonionic surfactant is preferably within the range of 6to 70 mass %, from the viewpoint of compatibility between the resin andthe fluorine-based nonionic surfactant, coatability of a thin filmhaving a thickness of several nm to several tens of nm, roughnessreduction of a coating film surface, and fluidity of an imprint layer tobe laminated after formation of a film. An example of a more specificcompound structure is preferably a fluorine-based nonionic surfactanthaving a fluorine-containing alkyl group and a polyoxyalkylene group.The number of carbon atoms in the fluorine-containing alkyl group ispreferably 1 to 25, more preferably 2 to 15, still more preferably 4 to10, and most preferably 5 to 8. The polyoxyalkylene group is preferablya polyoxyethylene group or a polyoxypropylene group. The number ofrepetitions of the polyoxyalkylene group is preferably 2 to 30, morepreferably 6 to 20, and still more preferably 8 to 15.

The fluorine-based nonionic surfactant is preferably a structurerepresented by General Formula (W1) or General Formula (W2).Rf¹-(L¹)_(a)-(OC_(p1)H_(2p1))_(q1)—O—R  General Formula (W1)Rf²¹-(L²¹)_(b)-(OC_(p2)H_(2p2))_(q2)—O-(L²²)_(c)-Rf²²  General Formula(W2)

Here, Rf¹, Rf²¹, and Rf²² represent a fluorine-containing group having 1to 25 carbon atoms, and R represents a hydrogen atom or an alkyl grouphaving 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms,or an aryl group having 6 to 8 carbon atoms.

L¹ and L²¹ represent a divalent linking group selected from a singlebond, —CH(OH)CH₂—, —O(C═O)CH₂—, and —OCH₂(C═O)—. L²² represents adivalent linking group selected from a single bond, —CH₂CH(OH)—,—CH₂(C═O)O—, and —(C═O)CH₂O—.

a, b, and c represent 0 or 1.

p1 and p2 represent an integer of 2 to 4, and q1 and q2 represent 2 to30.

Rf¹, Rf²¹, and Rf²² represent a fluorine-containing group having 1 to 25carbon atoms. Examples of the fluorine-containing group include aperfluoroalkyl group, a perfluoroalkenyl group, a ω-H-perfluoroalkylgroup, and a perfluoropolyether group. The number of carbon atoms ispreferably 1 to 25, more preferably 2 to 15, still more preferably 4 to10, and most preferably 5 to 8.

Specific examples of Rf¹, Rf²¹, and Rf²² include CF₃CH₂—, CF₃CF₂CH₂—,CF₃(CF₂)₂CH₂—, CF₃(CF₂)₃CH₂CH₂—, CF₃(CF₂)₄CH₂CH₂CH₂—, CF₃(CF₂)₄CH₂—,CF₃(CF₂)₅CH₂CH₂—, CF₃(CF₂)₅CH₂CH₂CH₂—, (CF₃)₂CH—, (CF₃)₂C(CH₃)CH₂—,(CF₃)₂CF(CF₂)₂CH₂CH₂—, (CF₃)₂CF(CF₂)₄CH₂CH₂—, H(CF₂)₂CH₂—, H(CF₂)₄CH₂—,H(CF₂)₆CH₂—, H(CF₂)₈CH₂—, (CF₃)₂C═C(CF₂CF₃)—, and{(CF₃CF₂)₂CF}₂C═C(CF₃)—. Among them, more preferred is CF₃(CF₂)₂CH₂—,CF₃(CF₂)₃CH₂CH₂—, CF₃(CF₂)₄CH₂—, CF₃(CF₂)₅CH₂CH₂—, or H(CF₂)₆CH₂—, andparticularly preferred is CF₃(CF₂)₅CH₂CH₂—.

R represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms,an alkenyl group having 2 to 8 carbon atoms, or an aryl group having 6to 8 carbon atoms. Among them, preferred is an alkyl group having 1 to 8carbon atoms.

Specific examples of R include a hydrogen atom, a methyl group, an ethylgroup, an n-propyl group, an isopropyl group, an n-butyl group, anisobutyl group, a sec-butyl group, a tert-butyl group, an n-pentylgroup, an isopentyl group, a neopentyl group, a hexyl group, a heptylgroup, an octyl group, a cyclopentyl group, a cyclohexyl group, an allylgroup, a phenyl group, a benzyl group, and a phenethyl group. Amongthem, more preferred is a hydrogen atom, a methyl group, an n-butylgroup, an allyl group, a phenyl group, or a benzyl group, andparticularly preferred is a hydrogen atom or a methyl group.

The polyoxyalkylene group (—(OC_(p1)H_(2p1))_(q1)— and—(OC_(p2)H_(2p2))_(q2)—) is selected from a polyoxyethylene group, apolyoxypropylene group, a polyoxybutylene group, and apoly(oxyethylene/oxypropylene) group, and is more preferably apolyoxyethylene group or a polyoxypropylene group and most preferably apolyoxyethylene group. The number of repetitions q1 or q2 is, onaverage, preferably 2 to 30, more preferably 6 to 20, and still morepreferably 8 to 16.

Specific compound examples of the fluorine-based nonionic surfactantrepresented by General Formula (W1) and General Formula (W2) include thefollowing.

Examples of commercially available fluorine-based nonionic surfactantinclude FLUORAD FC-4430 and FC-4431 (manufactured by Sumitomo 3MLimited), SURFLON S-241, S-242 and S-243 (manufactured by Asahi GlassCo., Ltd.), EFTOP EF-PN31M-03, EF-PN31M-04, EF-PN31M-05, EF-PN31M-06 andMF-100 (manufactured by Mitsubishi Materials Electronic Chemicals Co.,Ltd.), POLYFOX PF-636, PF-6320, PF-656 and PF-6520 (manufactured byOMNOVA Solutions Inc.), FTERGENT 250, 251, 222F, 212M and DFX-18(manufactured by Neos Company Limited), UNIDYNE DS-401, DS-403, DS-406,DS-451 and DSN-403N (manufactured by Daikin Industries Ltd.), MEGAFACEF-430, F-444, F-477, F-553, F-556, F-557, F-559, F-562, F-565, F-567,F-569 and R-40 (manufactured by DIC Corporation), and CAPSTONE FS-3100and ZONYL FSO-100 (manufactured by E.I. du Pont de Nemours and CompanyCo., Ltd.).

More preferred examples of the fluorine-based nonionic surfactantinclude POLYFOX PF-6520 and PF-6320, MEGAFACE F-444, and CAPSTONEFS-3100.

Examples of the hydrocarbon-based nonionic surfactant includepolyoxyalkylene alkyl ethers and polyoxyalkylene aryl ethers, sorbitanfatty acid esters, and fatty acid alkanol amides. Specific examples ofthe polyoxyalkylene alkyl ethers and polyoxyalkylene aryl ethers includepolyoxyethylene octyl ether, polyoxyethylene 2-ethylhexyl ether,polyoxyethylene lauryl ether, polyoxyethylene cetyl ether,polyoxyethylene oleyl ether, polyoxyethylene nonylphenyl ether, andpolyoxyethylene naphthyl ether. Specific examples of the sorbitan fattyacid esters include sorbitan laurate and sorbitan oleate,polyoxyethylene sorbitan laurate, and polyoxyethylene sorbitan oleate.Specific examples of the fatty acid alkanol amides include lauric aciddiethanol amide, and oleic acid diethanol amide.

Commercially available examples of the Si-based nonionic surfactantinclude SI-10 series (manufactured by Takemoto Oil & Fat Co., Ltd.),SH-3746, SH-3749, SH-3771, SH-8400, and TH-8700 (manufactured by DowCorning Toray Co., Ltd.), and Shin-Etsu silicones KP-322, KP-341,KF-351, KF-352, KF-353, KF-354L, KF-355A, and KF-615A (manufactured byShin-Etsu Chemical Co., Ltd).

Commercially available examples of the fluorine.Si-based nonionicsurfactant include X-70-090, X-70-091, X-70-092 and X-70-093(manufactured by Shin-Etsu Chemical Co., Ltd.), and MEGAFACE R-08 andXRB-4 (manufactured by DIC Corporation).

The content of the nonionic surfactant is preferably 0.01 to 25 parts bymass with respect to 100 parts by mass of the resin. The lower limitvalue is, for example, more preferably 0.5 parts by mass or more, andstill more preferably 0.1 parts by mass or more. The upper limit valueis, for example, more preferably 20 parts by mass or less, and stillmore preferably 15 parts by mass or less. If the content of the nonionicsurfactant is within the above-specified range, it is easy to obtain theeffect described above.

The nonionic surfactants may be used alone or in combination of two ormore thereof. In a case where two or more nonionic surfactants are usedin combination, the total amount thereof is within the above-specifiedrange.

<<Solvent>>

The resin composition for underlayer film formation according to thepresent invention contains a solvent. The solvent is preferably anorganic solvent, and more preferably an organic solvent having a boilingpoint of 80° C. to 200° C. at normal pressures. Any solvent may be usedas long as it is a solvent capable of dissolving individual componentsconstituting a resin composition for underlayer film formation. Examplesof the solvent include an organic solvent having any one or more of anester group, a carbonyl group, a hydroxyl group and an ether group. Morespecifically, preferred examples of the organic solvent includepropylene glycol monomethyl ether acetate (PGMEA), ethoxyethylpropionate, cyclohexanone, 2-heptanone, γ-butyrolactone, butyl acetate,propylene glycol monomethyl ether, and ethyl lactate. Among them, PGEMA,ethoxyethyl propionate, and 2-heptanone are more preferable, and PGMEAis particularly preferable. Two or more organic solvents may be used incombination thereof. A mixed solvent of an organic solvent having ahydroxyl group and an organic solvent having no hydroxyl group is alsopreferable.

The content of the organic solvent in the resin composition forunderlayer film formation is optimally adjusted depending on theviscosity of the composition and a desired film thickness of anunderlayer film. From the viewpoint of coatability, the amount of theorganic solvent to be added is preferably 95.0 to 99.99 mass %, morepreferably 96.0 to 99.95 mass %, and still more preferably 97.0 to 99.9mass %, with respect to the resin composition for underlayer filmformation.

<<Acid, and Thermal Acid Generator>>

The resin composition for underlayer film formation according to thepresent invention also preferably contains an acid and/or a thermal acidgenerator. By including an acid and/or a thermal acid generator, it ispossible to cure the resin composition for underlayer film formation ata relatively low heating temperature (also referred to as bakingtemperature).

Examples of the acid include p-toluenesulfonic acid, 10-camphorsulfonicacid, and perfluorobutane sulfonic acid.

The thermal acid generator is preferably a compound that generates anacid at 100° C. to 180° C. (more preferably, 120° C. to 180° C., andstill more preferably 120° C. to 160° C.). By setting the acidgeneration temperature to 100° C. or more, it is possible to ensure thetemporal stability of the resin composition for underlayer filmformation.

Examples of the thermal acid generator includeisopropyl-p-toluenesulfonate, cyclohexyl-p-toluenesulfonate, and anaromatic sulfonium salt compound named SAN-AID SI series manufactured bySanshin Chemical Industry Co., Ltd.

In the case of blending an acid and/or a thermal acid generator, theacid and/or the thermal acid generator is contained in an amount ofpreferably 0.1 to 10 parts by mass with respect to 100 parts by mass ofthe resin. The lower limit is more preferably 0.5 parts by mass or more.The upper limit is more preferably 5 parts by mass or less.

The content of the acid and/or the thermal acid generator is preferably0.0005 to 0.1 mass % with respect to the total amount of the resincomposition for underlayer film formation. The lower limit is morepreferably 0.0005 mass % or more. The upper limit is more preferably0.01 mass % or less, and still more preferably 0.005 mass % or less.

In the present invention, the acid and the thermal acid generator may beused in combination thereof or may be respectively used alone. Inaddition, acids and thermal acid generators may be respectively usedalone or in combination of two or more thereof.

<<Other Components>>

The resin composition for underlayer film formation according to thepresent invention may contain a crosslinking agent, a polymerizationinhibitor, and the like as other components. The amount of thesecomponents to be blended is preferably 50 mass % or less, morepreferably 30 mass % or less, and still more preferably 10 mass % orless, with respect to the total components of the resin composition forunderlayer film formation excluding the solvent. It is, however,particularly preferable to contain substantially no other components.The expression of “to contain substantially no other components” as usedherein means that the other components are not intentionally added tothe resin composition for underlayer film formation, except for, forexample, additives such as a reactant, a catalyst and a polymerizationinhibitor used for synthesis of the resin, and impurities derived fromreaction by-products. More specifically, the content of the othercomponents may be 5 mass % or less, and further 1 mass % or less.

<<<Crosslinking Agent>>>

The crosslinking agent is preferably a cation-polymerizable compoundsuch as an epoxy compound, an oxetane compound, a methylol compound, amethylol ether compound, or a vinyl ether compound.

Examples of the epoxy compound include EPOLITE manufactured by KyoeishaChemical Co., Ltd.; DENACOL EX manufactured by Nagase chemteXCorporation; EOCN, EPPN, NC, BREN, GAN, GOT, AK, and RE Seriesmanufactured by Nippon Kayaku Co., Ltd.; EPIKOTE manufactured by JapanEpoxy Resins Co., Ltd.; EPICLON manufactured by DIC Corporation; andTEPIC Series manufactured by Nissan Chemical Industries, Ltd. Two ormore thereof may be used in combination.

Examples of the oxetane compound include ETERNACOLL OXBP, OXTP, andOXIPA manufactured by Ube Industries, Ltd.; and ARON oxetane OXT-121 andOXT-221 manufactured by Toagosei Co., Ltd.

Examples of the vinyl ether compound include VECTOMER Seriesmanufactured by Allied Signal, Inc.

Examples of the methylol compound and methylol ether compound include aurea resin, a glycouril resin, a melamine resin, a guanamine resin, anda phenol resin. Specific examples thereof include NIKALAC MX-270,MX-280, MX-290, MW-390, and BX-4000 manufactured by Sanwa Chemical Co.,Ltd; and CYMEL 301, 303 ULF, 350, and 1123 manufactured by CytecIndustries Inc.

<<<Polymerization Inhibitor>>>

The preservation stability can be improved by including a polymerizationinhibitor in a resin composition for underlayer film formation. Examplesof the polymerization inhibitor include hydroquinone, p-methoxyphenol,di-tert-butyl-p-cresol, pyrogallol, tert-butylcatechol, benzoquinone,4,4′-thiobis(3-methyl-6-tert-butylphenol),2,2′-methylenebis(4-methyl-6-tert-butylphenol),N-nitrosophenylhydroxylamine cerous salt, phenothiazine, phenoxazine,4-methoxynaphthol, 2,2,6,6-tetramethylpiperidine-1-oxyl free radical,2,2,6,6-tetramethylpiperidine,4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radical,nitrobenzene, and dimethylaniline. Among them, phenothiazine,4-methoxynaphthol, 2,2,6,6-tetramethylpiperidine-1-oxyl free radical,2,2,6,6-tetramethylpiperidine, and4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radical arepreferable, since they exhibit polymerization inhibiting effects evenunder an oxygen-free condition.

<Preparation of Resin Composition for Underlayer Film Formation>

If the above-specified composition is satisfied, an underlayer filmhaving excellent surface flatness and adhesiveness is easily obtained.

The resin composition for underlayer film formation according to thepresent invention can be prepared by mixing the above-mentionedindividual components. Also, after mixing the individual components, itis preferred to filter the mixture through, for example a filter.Filtration may be carried out in multiple steps or may be repeated inmany times. It is also possible to re-filter the filtrate.

Any filter may be used without particular limitation as long as it isconventionally used for filtration or the like. For example, the filtermay be a filter made of a fluororesin such as polytetrafluoroethylene(PTFE), a polyamide-based resin such as nylon-6 or nylon-6,6, apolyolefin resin such as polyethylene or polypropylene (PP) (includingones having a high density and an ultra-high molecular weight), or thelike. Among these materials, preferred are polypropylene (includinghigh-density polypropylene) and nylon.

The pore size of the filter is suitably, for example, about 0.003 to 5.0μm. By specifying the pore size of the filter to be this range, itbecomes possible to reliably remove fine foreign materials such asimpurities and aggregates contained in the composition, whilesuppressing filtration clogging.

In the use of filter, different filters may be used in combination. Inthat case, filtering by a first filter may be carried out only once ortwo or more times. In a case of filtering two or more times by combiningdifferent filters, pore size for a second or subsequent filtering ispreferably made smaller than or equal to that for a first filtering. Inaddition, first filters having a different pore size in theabove-mentioned range may be used in combination. The pore size hereincan be set by referring to nominal values of filter manufacturers.Commercially available filters can be selected from various filterssupplied by, for example, Nihon Pall Ltd., Advantec Toyo Kaisha, Ltd.,Nihon Entegris K.K. (formerly Nihon Mykrolis K.K.) or Kitz Micro FilterCorporation.

<Properties of Resin Composition for Underlayer Film Formation>

The contact angle of the film formed by the resin composition forunderlayer film formation according to the present invention withrespect to water is preferably 50° or more, more preferably 52° or more,and still more preferably 55° or more. In addition, the contact anglewith respect to diiodomethane is preferably 30° or more, more preferably32° or more, and still more preferably 35° or more. According to thisaspect, when an imprint layer of a photocurable composition is formed onthe surface of the underlayer film formed by the resin composition forunderlayer film formation according to the present invention by a methodsuch as an inkjet method, the diameter of landed droplets of thephotocurable composition does not spread more than necessary and theheight is increased, consequently controllability of the inkjet landingmap corresponding to the pattern distribution formed by imprinting isimproved, whereby it is possible to reduce the distribution of the filmthickness of the residual film layer between the pattern bottom and thebase material after imprinting. When a substrate using the patternformed by imprinting is processed by dry etching or the like, a residualfilm removal process of first removing the residual film layer isnecessary, but it is possible to reduce in-plane distribution of theresidual film layer and consequently it is possible to suppress in-planedistribution of damage to the pattern line width due to the residualfilm removal process, whereby it becomes possible to maintain uniformityof the pattern line width after in-plane processing.

In the present invention, the contact angle of the film with respect towater and diiodomethane is calculated by taking the measurement valueobtained by a drop method as a contact angle. Specifically, the contactangle of the film is a value measured by a method of landing measurementsolvents such as water and diiodomethane in a state of 2 μL droplets onthe substrate surface which is a measurement target, using a contactangle meter DM-701 (manufactured by Kyowa Interface Science Co., Ltd)under the conditions of 25° C. and 45% RH, and then calculating acontact angle from droplet shapes after 500 ms following landing.

Further, in the present invention, the contact angle of the film withrespect to a photocurable composition is a value measured by thefollowing method. That is, the contact angle of the film is determinedby landing the photocurable composition in a size of 6 pL on thesubstrate surface to be measured by an inkjet method; with respect todroplet sizes at 120 seconds after landing, determining the diameter oflanded droplets based on images obtained by photographing a bright fieldimage of an optical microscope from the top surface of the substrate;and further calculating a contact angle with the substrate surface fromthe diameter obtained by sphere approximation and the liquid volume (6pL).

<Photocurable Composition>

The photocurable composition (preferably, a photocurable composition forimprints) used together with the resin composition for underlayer filmformation according to the present invention generally contains apolymerizable compound and a photopolymerization initiator.

<<Polymerizable Compound>>

The polymerizable compound is preferably a polymerizable monomer.Examples thereof include a polymerizable monomer having 1 to 6 groupscontaining an ethylenically unsaturated bond; an epoxy compound; anoxetane compound; a vinyl ether compound; a styrene derivative; andpropenyl ether and butenyl ether.

The polymerizable compound preferably has a polymerizable group which ispolymerizable with the polymerizable group of the resin contained in theresin composition for underlayer film formation according to the presentinvention. Among them, (meth)acrylate is preferable. Specific examplesthereof include those described in paragraphs “0020” to “0098” ofJP2011-231308A, the content of which is incorporated herein by referencein its entirety.

The content of the polymerizable compound is, for example, preferably 50to 99 mass %, more preferably 60 to 99 mass %, and still more preferably70 to 99 mass %, with respect to the total solid content of thephotocurable composition. In a case where two or more polymerizablecompounds are used, it is preferred that the total amount thereof iswithin the above-specified range.

The polymerizable compound is preferably a polymerizable compound havingan alicyclic hydrocarbon group and/or an aromatic group, and preferablycontains a polymerizable compound having an alicyclic hydrocarbon groupand/or an aromatic group, and a polymerizable compound having a siliconatom and/or a fluorine atom. The total content of the polymerizablecompounds having an alicyclic hydrocarbon group and/or an aromatic grouppreferably accounts for 30 to 100 mass %, more preferably 50 to 100 mass%, and still more preferably 70 to 100 mass % of the total polymerizablecompounds. The molecular weight of the polymerizable compound ispreferably of less than 1,000.

In a further preferable aspect, a (meth)acrylate polymerizable compoundhaving an aromatic group, used as the polymerizable compound, preferablyaccounts for 50 to 100 mass %, more preferably 70 to 100 mass %, andparticularly preferably 90 to 100 mass % of the total polymerizablecompounds.

In a particularly preferable aspect, a polymerizable compound (1)described below accounts for 0 to 80 mass % (more preferably 20 to 70mass %) of the total polymerizable compounds, a polymerizable compound(2) described below accounts for 20 to 100 mass % (more preferably 50 to100 mass %) of the total polymerizable compounds, and a polymerizablecompound (3) described below accounts for 0 to 10 mass % (morepreferably 0.1 to 6 mass %) of the total polymerizable compounds:

(1) a polymerizable compound having an aromatic group (preferably aphenyl group or a naphthyl group, and more preferably a naphthyl group)and a (meth)acryloyloxy group;

(2) a polymerizable compound having an aromatic group (preferably aphenyl group or a naphthyl group, and more preferably a phenyl group),and two (meth)acrylate groups; and

(3) a polymerizable compound having at least one of a fluorine atom or asilicon atom (more preferably a fluorine atom), and a (meth)acryloyloxygroup.

In a photocurable composition for imprints, the content of apolymerizable compound having a viscosity at 25° C. of less than 5 mPa·sis preferably 50 mass % or less, more preferably 30 mass % or less, andstill more preferably 10 mass % or less, with respect to the totalpolymerizable compounds. By setting the content of a polymerizablecompound to the above-specified range, inkjet ejection stability may beimproved, and thereby defects in imprint transfer may be reduced.

<<Photopolymerization Initiator>>

The photopolymerization initiator may be any compound which generates anactive species capable of polymerizing the above-described polymerizablecompound under photoirradiation. The photopolymerization initiator ispreferably a radical polymerization initiator or a cation polymerizationinitiator, and more preferably a radical polymerization initiator. Inthe present invention, a plurality of photopolymerization initiators maybe used in combination.

The radical photopolymerization initiator may be, for example,commercially available initiators. Those described, for example, inparagraph “0091” of JP2008-105414A may be preferably used. Among them,an acetophenone-based compound, an acylphosphine oxide-based compound,and an oxime ester-based compound are preferable from the viewpoints ofcuring sensitivity and absorption properties. Examples of commerciallyavailable products include Irgacure (registered trademark) 907(manufactured by BASF SE).

The content of the photopolymerization initiator is, for example,preferably 0.01 to 15 mass %, more preferably 0.1 to 12 mass %, andstill more preferably 0.2 to 7 mass %, with respect to the total solidcontent of the photocurable composition. In a case where two or morephotopolymerization initiators are used, the total content thereofpreferably falls in the above-specified ranges. In a case where thecontent of the photopolymerization initiator is 0.01 mass % or more,there will be preferable trends of improvements in sensitivity (fastcurability), resolution, line edge roughness, and coating film strength.On the other hand, in a case where the content of thephotopolymerization initiator is 15 mass % or less, there will bepreferable trends of improvements in light transmittance, colorability,and handleability.

<<Surfactant>>

The photocurable composition preferably contains a surfactant.

The surfactant may be, for example, those nonionic surfactants describedfor the resin composition for underlayer film formation as describedabove. Examples of the surfactant usable in the present invention may bereferred to paragraph “0097” of JP2008-105414A, the content of which isincorporated herein by reference in its entirety. The surfactant is alsocommercially available, and an example thereof includes PF-636(manufactured by OMNOVA Solutions Inc.).

The content of the surfactant is, for example, 0.001 to 5 mass %,preferably 0.002 to 4 mass %, and still more preferably 0.005 to 3 mass%, with respect to the total solid content of the photocurablecomposition. In a case where two or more surfactants are used, the totalcontent thereof preferably falls in the above-specified ranges. If thecontent of the surfactant falls in the range from 0.001 to 5 mass % ofthe composition, an effect on uniformity of coating will be good.

<<Non-Polymerizable Compound>>

The photocurable composition may contain a non-polymerizable compoundwhich has, at the terminal thereof, at least one hydroxyl group or apolyalkylene glycol structure formed by etherifying the hydroxyl group,and contains substantially no fluorine atom and silicon atom.

The content of the non-polymerizable compound is, for example,preferably 0.1 to 20 mass %, more preferably 0.2 to 10 mass %, stillmore preferably 0.5 to 5 mass %, and even more preferably 0.5 to 3 mass%, with respect to the total solid content of the photocurablecomposition.

<<Antioxidant>>

The photocurable composition preferably contains an antioxidant.

The antioxidant is for preventing fading by heat or photoirradiation,and for preventing fading by various oxidized gases such as ozone,active hydrogen, NOx, and SOx (X is an integer). Incorporation of anantioxidant into the photocurable composition brings about advantagesthat the cured film is prevented from being colored and the filmthickness is prevented from being reduced due to decomposition of thecured film.

Examples of the antioxidant includes hydrazides, hindered amine-basedantioxidants, nitrogen-containing heterocyclic mercapto-based compounds,thioether-based antioxidants, hindered phenol-based antioxidants,ascorbic acids, zinc sulfate, thiocyanates, thiourea derivatives,saccharides, nitrites, sulfites, thiosulfates, and hydroxylaminederivatives. Among them, particularly preferred are hinderedphenol-based antioxidants and thioether-based antioxidants from theviewpoint of their effect of preventing cured film coloration andpreventing film thickness reduction.

Commercial products of the antioxidant include trade name Irganox(registered trademark) 1010, 1035, 1076, and 1222 (all manufactured byBASF SE); trade name Antigene P, 3C, FR, SUMILIZER S, and SUMILIZER GA80(manufactured by Sumitomo Chemical Co., Ltd.), and trade name ADEKASTABAO70, AO80, and AO503 (manufactured by Adeka). These antioxidants may beused alone or in combination thereof.

The content of the antioxidant is, for example, 0.01 to 10 mass %, andpreferably 0.2 to 5 mass %, with respect to the polymerizable compound.In a case where two or more antioxidants are used, the total amountthereof preferably falls within the above-specified range.

<<Polymerization Inhibitor>>

The photocurable composition preferably contains a polymerizationinhibitor. By including the polymerization inhibitor, there is atendency capable of suppressing a change in viscosity over time,occurrence of foreign materials and deterioration of patternformability.

The content of the polymerization inhibitor is, for example, 0.001 to 1mass %, preferably 0.005 to 0.5 mass %, and more preferably 0.008 to0.05 mass %, with respect to the polymerizable compound, and a change inviscosity over time can be inhibited while maintaining a high curingsensitivity by blending the polymerization inhibitor in an appropriateamount. The polymerization inhibitor may be contained in thepolymerizable compound to be used in advance or may be further added tothe photocurable composition.

Specific examples of the polymerization inhibitor may be referred to thedescription in paragraph “0125” of JP2012-094821A, the content of whichis incorporated herein by reference in its entirety.

<<Solvent>>

The photocurable composition may contain a solvent, if necessary. Apreferred solvent is a solvent having a boiling point of 80° C. to 200°C. at normal pressures. Regarding the type of the solvent, any solventcapable of dissolving individual components may be used, and examplesthereof include the same solvents as those described for theabove-mentioned resin composition for underlayer film formation. Amongthem, most preferred is a solvent containing propylene glycol monomethylether acetate from the viewpoint of coating uniformity.

The content of the solvent in the photocurable composition is optimallyadjusted depending on the viscosity, coatability, and desired filmthickness of the photocurable composition. From the viewpoint ofimproving coatability, the content of the solvent in the photocurablecomposition may be preferably in the range of 99 mass % or less. In acase where the photocurable composition is applied onto a base materialby an inkjet method, it is preferred that the photocurable compositioncontains substantially no solvent (for example, 3 mass % or less). Onthe other hand, when a pattern having a film thickness of 500 nm or lessis formed by a spin-coating method or the like, the content of thesolvent may be 20 to 99 mass %, preferably 40 to 99 mass %, andparticularly preferably 70 to 98 mass %.

<<Polymer Component>>

The photocurable composition may further contain a polymer component,from the viewpoint of improving dry etching resistance, imprintsuitability, curability, and the like. The polymer component ispreferably a polymer having a polymerizable group in the side chainthereof. The mass-average molecular weight of the polymer component ispreferably 2,000 to 100,000, and more preferably 5,000 to 50,000, fromthe viewpoint of compatibility with a polymerizable compound. Thecontent of the polymer component is preferably 0 to 30 mass %, morepreferably 0 to 20 mass %, still more preferably 0 to 10 mass %, andmost preferably 0 to 2 mass %, with respect to the total solid contentof the photocurable composition.

In a photocurable composition for imprints, since pattern formabilitymay be improved if the content of a compound having a molecular weightof 2,000 or larger is 30 mass % or less, a lower content of polymercomponents is preferable, and therefore it is preferred that thephotocurable composition contains substantially no polymer components,except for a surfactant or trace amounts of additives.

In addition to the above-mentioned components, the photocurablecomposition may contain a mold release agent, a silane coupling agent,an ultraviolet absorber, a light stabilizer, an antiaging agent, aplasticizer, an adhesion promoter, a thermal polymerization initiator, acolorant, elastomer particles, a photoacid amplifier, a photobasegenerator, a basic compound, a fluidity controlling agent, ananti-foaming agent, or a dispersant, if desired.

The photocurable composition may be prepared by mixing the individualcomponents described above. Mixing of the individual components isgenerally carried out in a temperature range of 0° C. to 100° C. Aftermixing of the individual components, for example, the mixture ispreferably filtered through a filter having a pore size of 0.003 to 5.0μm. The filtration may be carried out in a multi-stage manner, or may berepeated a plurality of times. Examples of the filter material andmethod include those described for the resin composition for underlayerfilm formation, and a preferred range thereof is also the same.

In the photocurable composition, a mixture of the total componentsexcluding a solvent preferably has a viscosity of 100 mPa·s or smaller,more preferably 1 to 70 mPa·s, still more preferably 2 to 50 mPa·s, andmost preferably 3 to 30 mPa·s.

The photocurable composition after manufacturing thereof is bottled in acontainer such as a gallon bottle or a coated bottle, and transported orstored. In this case, the inner space of the container may be replacedwith an inert gas such as nitrogen or argon, for the purpose ofpreventing deterioration. While the photocurable composition may betransported or stored at normal temperature, it is also preferable tocontrol the temperature in the range from −20° C. to 0° C. for thepurpose of preventing denaturation. Of course, the photocurablecomposition may be shielded from light up to a level of suppressing thereaction from proceeding.

A permanent film (a resist for structural members) for use in aliquid-crystal display (LCD) or the like and a resist for use insubstrate processing for electronic materials are strongly required toavoid contamination by metallic or organic ionic impurities, in orderthat operations of the product will not be interfered. In a case wherethe photocurable composition is used for such an application, theconcentration of the metallic or organic ionic impurities in thephotocurable composition is preferably 1 ppm or less, more preferably100 ppb or less, and still more preferably 10 ppb or less.

<Layered Product>

The layered product of the present invention has, on the surface of abase material, an underlayer film formed by curing the above-mentionedresin composition for underlayer film formation according to the presentinvention.

The thickness of the underlayer film is not particularly limited, but itis preferably 1 to 10 nm, and more preferably 2 to 5 nm.

The base material is not particularly limited and is selectabledepending on a variety of applications. Examples of the base materialinclude quartz, glass, an optical film, a ceramic material, anevaporated film, a magnetic film, a reflective film, a metal substratesuch as a Ni, Cu, Cr or Fe substrate, a paper, Spin On Carbon (SOC),Spin On Glass (SOG), a polymer substrate such as a polyester film, apolycarbonate film or a polyimide film, a thin film transistor (TFT)array substrate, an electrode plate of plasma display panel (PDP), aconductive substrate such as an Indium Tin Oxide (ITO) or metalsubstrate, an insulating substrate, and a substrate used insemiconductor manufacturing such as silicon, silicon nitride,polysilicon, silicon oxide or amorphous silicon. In the presentinvention, an appropriate underlayer film may be formed particularlyeven when a substrate having a small surface energy (for example, about40 to 60 mJ/m²) is used. Meanwhile, in a case where the base material isintended to be etched, a substrate used in semiconductor manufacturingis preferable.

In the present invention, in particular, a base material having a polargroup on the surface thereof may be preferably used. By using the basematerial having a polar group on the surface thereof, there is atendency of further improvements in adhesiveness to a resin compositionfor underlayer film formation. Examples of the polar group include ahydroxyl group, a carboxyl group, and a silanol group. A siliconsubstrate and a quartz substrate are particularly preferable.

The geometry of the substrate is also not particularly limited, and maybe plate-shaped or roll-shaped. The substrate is also selectable fromthose of light transmissive and non-light transmissive types, dependingon combination with a mold, or the like.

A pattern formed of the above-mentioned photocurable composition may beformed on the surface of the underlayer film. The pattern may be used,for example, as an etching resist. The base material in this case isexemplified by a substrate (silicon wafer) having a thin film of Spin OnCarbon (SOC), Spin On Glass (SOG), SiO₂, or silicon nitride formedthereon. Multiple etching onto a base material may be carried out at thesame time.

The layered product having a pattern formed thereon may be used as apermanent film in devices or structures, in an intact form, or in a formobtained after removing any residual film in recessed portions orremoving the underlayer film. Such a layered product is less causativeof film separation and is therefore useful, even under environmentalchanges or stress applied thereto.

<Method for Forming Pattern>

Next, the method for forming a pattern according to the presentinvention will be described.

The method for forming a pattern according to the present inventionincludes a step of applying the resin composition for underlayer filmformation according to the present invention onto the surface of a basematerial in the form of layer; a step of heating the applied resincomposition for underlayer film formation to form an underlayer film; astep of applying a photocurable composition onto the surface of theunderlayer film in the form of layer; a step of pressing a mold having apattern on the photocurable composition; a step of curing thephotocurable composition by photoirradiation, while keeping it pressedunder the mold; and separating the mold. In particular, in the presentinvention, the step of forming an underlayer film is capable of formingan underlayer film having high adhesiveness to a cured film (an imprintlayer, or the like) of a photocurable composition, and excellent surfaceflatness, even when a baking temperature is low (for example, 120° C. to160° C.).

FIG. 1 is a schematic view illustrating an example of a manufacturingprocess when a photocurable composition for imprints is used for etchingof a base material, in which reference numeral 1 stands for a basematerial, 2 stands for an underlayer film, 3 stands for an imprintlayer, and 4 stands for a mold. In FIG. 1, a resin composition forunderlayer film formation is applied onto the surface of the basematerial 1 (2), the photocurable composition for imprints is appliedonto the surface (3), and the mold is applied onto the surface thereof(4). After photoirradiation is carried out, the mold is separated (5).Etching is carried out according to a pattern (an imprint layer 3)formed by the photocurable composition for imprints (6), and the imprintlayer 3 and the underlayer film 2 are separated to thereby form a basematerial with a desired pattern formed thereon (7). The adhesivenessbetween the base material 1 and the imprint layer 3 is important, sincea poor level of the adhesiveness between the base material 1 and theimprint layer 3 results in failing to exactly transfer the pattern ofthe mold 4.

Hereinafter, details of the method for forming a pattern according tothe present invention will be described.

<<Step of Applying Resin Composition for Underlayer Film Formation>>

First, a resin composition for underlayer film formation is applied ontothe surface of a base material in the form of layer. The method ofapplying a resin composition for underlayer film formation is preferablya coating method. Examples of the coating method include dip coating,air knife coating, curtain coating, wire bar coating, gravure coating,extrusion coating, spin coating, slit scan coating, and inkjet coating.Spin coating is preferable from the viewpoint of film thicknessuniformity.

The coating amount of the resin composition for underlayer filmformation is, for example, preferably 1 to 10 nm, and more preferably 3to 8 nm in terms of film thickness after curing.

<<Step of Forming Underlayer Film>>

Next, the resin composition for underlayer film formation applied ontothe base material surface is heated to form an underlayer film.

The resin composition for underlayer film formation applied onto thebase material surface is preferably dried to remove a solvent. Apreferred drying temperature is 70° C. to 130° C.

After carrying out a drying step if necessary, the resin composition forunderlayer film formation is heated and cured to form an underlayerfilm. Regarding the heating conditions, it is preferred that the heatingtemperature (baking temperature) is 120° C. to 250° C., and the heatingtime is 30 seconds to 10 minutes.

In the case where the resin composition for underlayer film formationcontains substantially no acid and thermal acid generator, the bakingtemperature is more preferably 160° C. to 250° C., and still morepreferably 180° C. to 250° C.

In the case where the resin composition for underlayer film formationcontains an acid or a thermal acid generator, the baking temperature ismore preferably 120° C. to 180° C., and still more preferably 120° C. to160° C.

The step of removing a solvent and the curing step may be carried out atthe same time.

In the present invention, it is preferred that the resin composition forunderlayer film formation is applied onto the base material surface,followed by heating to cure at least a portion of the resin compositionfor underlayer film formation, and then a photocurable composition isapplied onto the surface of the underlayer film. When such means isadopted, the resin composition for underlayer film formation is alsocompletely cured at the time of photocuring the photocurablecomposition, whereby there is a tendency that adhesiveness is furtherimproved.

<<Step of Applying Photocurable Composition>>

Next, a photocurable composition is applied onto the surface of theunderlayer film in the form of layer. The method of applying aphotocurable composition may employ the same method as theabove-mentioned application method of a resin composition for underlayerfilm formation.

The film thickness of the patterning layer composed of the photocurablecomposition may vary depending on purpose of use. For example, the filmthickness after drying is preferably about 0.03 to 30 μm. Thephotocurable composition may be applied by multiple applications. In amethod of placing liquid droplets on the underlayer film by an inkjetmethod or the like, the volume of liquid droplets is preferably 1 pl to20 pl. The liquid droplets are preferably arranged on the underlayerfilm while keeping a space therebetween.

<<Step of Pressing Mold>>

Next, a mold is pressed against the surface of the patterning layer fortransferring the pattern from the mold onto the patterning layer.Accordingly, the fine pattern previously formed on the pressing surfaceof the mold can be transferred onto the patterning layer.

Alternatively, the photocurable composition may be applied over the moldhaving a pattern formed thereon, and the underlayer film may be pressedthereto.

When the mold is pressed against the patterning layer surface, heliummay be introduced between the mold and the patterning layer surface. Byusing such a method, the permeation of gases through the mold ispromoted, so it is possible to facilitate the elimination of residualair bubbles. Further, it is possible to suppress radical polymerizationinhibition in the exposure by reducing the dissolved oxygen in thepatterning layer. Alternatively, a condensable gas instead of helium maybe introduced between the mold and the patterning layer. By using such amethod, it is possible to further accelerate the disappearance ofresidual air bubbles by utilizing the fact that the introducedcondensable gas is condensed to result in a decrease of the volumethereof. The condensable gas refers to a gas which is condensed bytemperature and pressure, and for example, trichlorofluoromethane,1,1,1,3,3-pentafluoropropane, or the like may be used. The condensablegas may be referred to, for example, the description of paragraph “0023”of JP2004-103817A and paragraph “0003” of JP2013-254783A, the contentsof which are incorporated herein by reference in their entirety.

A mold material is described. In photo-nanoimprint lithography using aphotocurable composition, a light transmissive material is selected forat least one of a mold material and/or a base material. In thephoto-nanoimprint lithography applied to the present invention, thephotocurable composition is applied onto a base material to form apatterning layer thereon, and a light transmissive mold is pressedagainst the surface of the layer which is then irradiated with lightfrom the back of the mold to thereby cure the patterning layer.Alternatively, the photocurable composition is applied onto a lighttransmissive base material, and a mold is pressed thereagainst, followedby irradiation with light from the back of the base material whereby thephotocurable composition can be cured.

The photoirradiation may be carried out while the mold is kept incontact with the patterning layer or after the mold is separated. In thepresent invention, the photoirradiation is preferably carried out whilethe mold is kept in contact with the patterning layer.

The mold usable in the present invention has a pattern to betransferred. The pattern on the mold may be formed with a desired levelof processing accuracy, for example, by photolithography, electron beamlithography, or the like. The method for forming a pattern on the moldis not particularly limited in the present invention. Also a patternformed by the method for forming a pattern according to the presentinvention may be used as a mold.

The light transmissive mold material for use in the present invention isnot particularly limited and may be any one having a predeterminedstrength and durability. Specific examples of the light transmissivemold material include glass, quartz, a light-transparent resin such asan acrylic resin or a polycarbonate resin, a transparent evaporatedmetal film, a flexible film of polydimethylsiloxane or the like, aphotocured film, and a metal film.

The material for a non-light transmissive mold to be used in the casewhere a light transmissive base material is used is not particularlylimited and may be any one having a predetermined strength. Specificexamples of the non-light transmissive mold material include, but arenot particularly limited to, a ceramic material, an evaporated film, amagnetic film, a reflective film, a metal substrate of Ni, Cu, Cr, Fe,or the like, SiC, silicon, silicon nitride, polysilicon, silicon oxide,and amorphous silicon. The shape of the mold is not also particularlylimited, and may be any of a plate-shaped mold or a roll-shaped mold.The roll-shaped mold is applied especially when continuous transfer inpatterning is desired.

The mold for use in the present invention may be subjected to a surfacerelease treatment for the purpose of enhancing the releasability of thephotocurable composition from the mold. The mold of such a type includesthose surface-treated with a silicon-based or fluorine-based silanecoupling agent, for which, for example, commercially available moldrelease agents such as OPTOOL DSX manufactured by Daikin Industries,Ltd., and Novec EGC-1720 manufactured by Sumitomo 3M Ltd. may besuitably used.

In the case where photo-nanoimprint lithography is carried out using thephotocurable composition, the mold pressure in the method for forming apattern according to the present invention is preferably 10 atmospheresor lower. When the mold pressure is 10 atmospheres or lower, then themold and the base material are hardly deformed and the patterningaccuracy tends to increase. It is also preferable since there is atendency that the apparatus may be small-sized because the pressure tobe given to the mold is low. The mold pressure is preferably selectedfrom the region capable of securing the mold transfer uniformity, withina range by which the residual film of the photocurable composition forimprints in the area of mold pattern projections may be reduced.

<<Step of Curing Photocurable Composition>>

Then, the photocurable composition is cured by photoirradiation in astate where the mold is the pressed against the patterning layer. Thedose of photoirradiation may be sufficiently larger than the dosenecessary for curing of the photocurable composition. The dose necessaryfor curing may be suitably determined depending on the degree ofconsumption of the unsaturated bonds in the photocurable composition andon the tackiness of the cured film as previously determined.

In the photo-nanoimprint lithography applied to the present invention,photoirradiation is carried out while keeping the substrate temperaturegenerally at room temperature, where the photoirradiation mayalternatively be carried out under heating for the purpose of enhancingthe reactivity. Photoirradiation can also be carried out in vacuo, sincea vacuum conditioning prior to the photoirradiation is effective forpreventing entrainment of air bubbles, for suppressing the reactivityfrom being reduced due to incorporation of oxygen, and for improving theadhesiveness between the mold and the photocurable composition. In themethod for forming a pattern according to the present invention, thedegree of vacuum in the process of photoirradiation is preferably in therange from 10⁻¹ Pa to normal pressure.

The light to be used for curing the photocurable composition is notparticularly limited, and examples thereof include light and radiationswith a wavelength falling within a range of high-energy ionizingradiation, near-ultraviolet, far-ultraviolet, visible, infrared, and thelike. The high-energy ionizing radiation source includes, for example,accelerators such as Cockcroft accelerator, Van De Graaff accelerator,linear accelerator, betatron, and cyclotron. The electron beamsaccelerated by such an accelerator are used most industriallyconveniently and most economically; but any other radioisotopes andother radiations from nuclear reactors, such as γ-rays, X-rays, α-rays,neutron beams, and proton beams may also be used. The UV sourcesinclude, for example, UV fluorescent lamp, low-pressure mercury lamp,high pressure mercury lamp, ultra-high pressure mercury lamp, xenonlamp, carbon arc lamp, and solar lamp. The radiations include, forexample, microwaves and extreme ultraviolet rays (EUV). In addition, alight emitting diode (LED), semiconductor laser light, or laser lightused in microfabrication of semiconductors, such as 248 nm KrF excimerlaser light, and 193 nm ArF excimer laser light can also be suitablyused in the present invention. These lights may be monochromatic lightsor may be lights of different wavelengths (mixed light).

When the exposure is carried out, the light intensity is desired to bewithin the range of 1 to 50 mW/cm². When the light intensity is 1 mW/cm²or more, then the producibility may increase since the exposure time maybe reduced; and when the light intensity is 50 mW/cm² or less, then itis preferable since there is a tendency that the properties of thepermanent film formed may be prevented from being degraded owing to sidereaction. The exposure dose is desired to be within the range of 5 to1,000 mJ/cm². When the exposure dose is within such a range, curabilityof the photocurable composition is favorable. Further, when the exposureis carried out, the oxygen concentration in the atmosphere may becontrolled to be less than 100 mg/L by introducing an inert gas such asnitrogen or argon into the system for preventing the radicalpolymerization from being inhibited by oxygen.

In the present invention, after the patterning layer (a layer composedof the photocurable composition) is cured through photoirradiation, ifdesired, the cured pattern may be further cured under heat giventhereto. The heating temperature is, for example, preferably 150° C. to280° C., and more preferably 200° C. to 250° C. The heating time is, forexample, preferably 5 to 60 minutes, and more preferably 15 to 45minutes.

<<Step of Separating Mold>>

A pattern according to the shape of a mold can be formed by curing thephotocurable composition as described above, and then separating themold.

Since the resin composition for underlayer film formation according tothe present invention exhibits excellent adhesiveness to the patterninglayer, it is possible to suppress separation of the patterning layer atthe time of separating the mold. Further, a surface flatness of theunderlayer film is satisfactory, and the surface flatness of thepatterning layer is also favorable.

Specific examples of the method for forming a pattern include themethods described in paragraphs “0125” to “0136” of JP2012-169462A, thecontent of which is incorporated herein by reference in its entirety.

Further, the method for forming a pattern according to the presentinvention can be applied to a pattern reversal method. The patternreversal method is carried out as follows. Specifically, a resistpattern is formed on a base material such as a carbon film (SOC) by themethod for forming a pattern according to the present invention.Subsequently, the resist pattern is coated with such a Si-containingfilm (SOG), an upper portion of the Si-containing film is subjected toetching back such that the resist pattern is exposed, and then theexposed resist pattern is removed by oxygen plasma or the like, wherebyit is possible to form a reversal pattern of the Si-containing film.Further, using the reversal pattern of the Si-containing film as anetching mask, the base material thereunder is etched whereby thereversal pattern is transferred onto the base material. Finally, usingthe base material having the reversal pattern transferred thereon as anetching mask, the base material is etching-processed. Examples of such amethod can be referred to JP1993-267253A (JP-H05-267253A),JP2002-110510A, and paragraphs “0016” to “0030” of JP2006-521702A, thecontents of which are incorporated herein by reference in theirentirety.

<Imprint Forming Kit>

Next, an imprint forming kit of the present invention will be described.

The imprint forming kit of the present invention includes theabove-mentioned resin composition for underlayer film formation and aphotocurable composition.

The composition and preferred range of each of the resin composition forunderlayer film formation and the photocurable composition are the sameas those described above.

The imprint forming kit of the present invention can be preferably usedin the above-mentioned method for forming a pattern.

In the imprint forming kit of the present invention, the contact angleof the film formed of the resin composition for underlayer filmformation with respect to the photocurable composition is preferably 10°or more, more preferably 15° or more, and still more preferably 20° ormore. The upper limit is, for example, preferably 60° or less, morepreferably 55° or less, and still more preferably 50° or less. Accordingto this aspect, a thickness of a residual film after mold pressing issmall, and therefore it is possible to carry out imprint formation wherea variation hardly occurs in the line width distribution afterprocessing.

<Process for Producing Device>

The process for producing a device according to the present inventionincludes the above-mentioned method for forming a pattern.

That is, a device can be produced by forming a pattern using theabove-mentioned method and then applying the method used in theproduction of various devices.

The pattern may be included as a permanent film in the device. Also,using the pattern as an etching mask, the base material may also besubjected to an etching process. For example, the base material issubjected to dry etching using the pattern as an etching mask to therebyselectively remove the upper layer portion of the base material. Thebase material is repeatedly subjected to such processing, whereby it ispossible to manufacture a device. The device may be, for example, asemiconductor device such as a large-scale integrated circuit (LSI).

EXAMPLES

Hereinafter, this invention will be described in more detail withreference to Examples. Materials, amounts to be used, ratios, details ofprocesses, and procedures of processes described in the followingExamples may be modified suitably, without departing from the spirit ofthis invention. Therefore, the scope of this invention is not limitedthereto. The expressions “parts” and “%” are based on mass unlessotherwise specified.

The expression “-co-” in the name of a polymer refers to that thesequence of monomer units of the polymer is non-specified.

<Synthesis of Resin A-3>

Propylene glycol monomethyl ether acetate (PGMEA) (28.5 g) was chargedinto a flask which was then warmed to 90° C. under a nitrogenatmosphere. To the solution was added dropwise over 4 hours a mixture ofglycidyl methacrylate (GMA, manufactured by Wako Pure ChemicalIndustries, Ltd.) (14.2 g), 1-ethylcyclopentylmethacrylate (EtCPMA,manufactured by Osaka Organic Chemical Industry Ltd.) (18.2 g), Dimethyl2,2′-azobis(2-methylpropionate) (V-601, manufactured by Wako PureChemical Industries, Ltd.) (1.1 g) and PGMEA (28.5 g). After completionof the dropwise addition, the reaction mixture was further stirred at90° C. for 4 hours to obtain a PGMEA solution of the GMA polymer.

To the solution of the GMA polymer were added acrylic acid (AA,manufactured by Wako Pure Chemical Industries, Ltd.) (15.0 g),tetrabutylammonium bromide (TBAB, manufactured by Wako Pure ChemicalIndustries, Ltd.) (2.0 g), and4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radicals(4-HO-TEMPO, manufactured by Wako Pure Chemical Industries, Ltd.) (50mg), followed by reaction at 90° C. for 10 hours. After the completionof the reaction, 200 mL of ethyl acetate was added thereto, followed byseparatory extraction with aqueous sodium bicarbonate and then diluteaqueous hydrochloric acid to remove excess acrylic acid and TBAB of thecatalyst. Finally, the extract was washed with pure water. This wasfollowed by concentration under reduced pressure and distilling of ethylacetate. The resulting resin A-3 had a mass-average molecular weight of15100 and a dispersity (mass-average molecular weight/number-averagemolecular weight) of 1.8.

<Synthesis of Resin A-1>

Resin A-1 was synthesized in the same manner as in Synthesis Example ofresin A-3, except that 25.6 g of GMA and 3.6 g of EtCPMA were used. Theresulting resin A-1 had a mass-average molecular weight of 20300 and adispersity (mass-average molecular weight/number-average molecularweight) of 2.0.

<Synthesis of Resin A-2>

Resin A-2 was synthesized in the same manner as in Synthesis Example ofresin A-3, except that 19.9 g of GMA and 10.9 g of EtCPMA were used. Theresulting resin A-2 had a mass-average molecular weight of 17800 and adispersity (mass-average molecular weight/number-average molecularweight) of 1.9.

<Synthesis of Resin A-4>

Resin A-4 was synthesized in the same manner as in Synthesis Example ofresin A-3, except that 8.5 g of GMA and 25.5 g of EtCPMA were used. Theresulting resin A-4 had a mass-average molecular weight of 13500 and adispersity (mass-average molecular weight/number-average molecularweight) of 1.8.

<Synthesis of Resin A-5>

Resin A-5 was synthesized in the same manner as in Synthesis Example ofresin A-3, except that 2.8 g of GMA and 32.8 g of EtCPMA were used. Theresulting resin A-5 had a mass-average molecular weight of 12,000 and adispersity (mass-average molecular weight/number-average molecularweight) of 1.8.

<Synthesis of Resins A-6 to A-10>

Resins A-6 to A-10 were synthesized by changing the monomers inSynthesis Example of resin A-3.

<Synthesis of Resin A2-1>

Poly[(phenyl glycidyl ether)-co-formaldehyde] (Mn=570, manufactured bySigma-Aldrich) (64.9 g) was dissolved in 150 g of propylene glycolmonomethyl ether acetate (PGEMA).

To the above solution were added β-carboxyethyl acrylate (manufacturedby Wako Pure Chemical Industries, Ltd.) (51.9 g), tetraethylammoniumbromide (TBAB, manufactured by Wako Pure Chemical Industries, Ltd.) (2.1g), and 4-hydroxy-tetramethylpiperidine-1-oxyl (4-HO-TEMPO, manufacturedby Wako Pure Chemical Industries, Ltd.) (50 mg), followed by reaction at90° C. for 10 hours. The resulting resin A2-1 had a mass-averagemolecular weight of 1500. The molar ratio of an acryloyloxy group:aglycidyl group calculated from the area ratio of H-NMR was 90:10.

<Synthesis of Resin A2-2>

Poly[(o-cresyl glycidyl ether)-co-formaldehyde] (Mn=1080, manufacturedby Sigma-Aldrich) (70.5 g) was dissolved in PGEMA (150 g).

To the above solution were added acrylic acid (AA, manufactured by WakoPure Chemical Industries, Ltd.) (23.1 g), TBAB (2.1 g), and 4-HO-TEMPO(50 mg), followed by reaction at 90° C. for 10 hours. The resultingresin A2-2 had a mass-average molecular weight of 2800. The molar ratioof an acryloyloxy group:a glycidyl group calculated from the area ratioof H-NMR was 80:20.

<Synthesis of Resin A2-3>

Poly(p-hydroxystyrene) (mass-average molecular weight=3500,dispersivity=1.4, VP-2500 manufactured by Nippon Soda Co., Ltd.) (48.1g), t-butoxy potassium (manufactured by Wako Pure Chemical Industries,Ltd.) (47.1 g), and t-butanol (manufactured by Wako Pure ChemicalIndustries, Ltd.) (1,000 g) were mixed.

Epichlorohydrin (manufactured by Wako Pure Chemical Industries, Ltd.)(38.9 g) was slowly added dropwise while maintaining the above solutionat 40° C., followed by reaction at 40° C. for 24 hours. Followingconcentration after the completion of the reaction, PGMEA (300 g) wasadded and the precipitated salt was separated by filtration.

To the filtrate were added AA (23.1 g), TBAB (2.1 g) and 4-HO-TEMPO (50mg), followed by reaction at 90° C. for 10 hours. The resulting resinA2-3 had a mass-average molecular weight of 8,000 and a dispersivity of1.6. The molar ratio of an acryloyloxy group:a glycidyl group calculatedfrom the area ratio of H-NMR was 80:20.

<Synthesis of Resin A2-6>

PGMEA (100 g) was placed in a flask, and the temperature was raised to90° C. under a nitrogen atmosphere. To the solution was added dropwiseover 2 hours a mixture of glycidyl methacrylate (GMA, manufactured byWako Pure Chemical Industries, Ltd.) (56.9 g) and Dimethyl2,2′-azobis(2-methylpropionate) (V-601, manufactured by Wako PureChemical Industries, Ltd.) (3.7 g), PGMEA (50 g). After completion ofthe dropwise addition, further stirring was carried out at 90° C. for 4hours to obtain a PGMEA solution of the GMA polymer.

To the solution of the GMA polymer were added AA (23.1 g), TBAB (2.1 g)and 4-HO-TEMPO (50 mg), followed by reaction at 90° C. for 10 hours. Theresulting resin A2-6 had a mass-average molecular weight of 14,000 and adispersivity of 2.0. The molar ratio of an acryloyloxy group:a glycidylgroup calculated from the area ratio of H-NMR was 80:20.

<Synthesis of Resin A2-4>

Resin A2-4 was synthesized in the same manner as in Synthesis Example ofResin A2-6, except that the additive amount of acrylic acid was changedto 28.0 g. The resulting resin A2-4 had a mass-average molecular weightof 14900 and a dispersivity of 2.1. The molar ratio of an acryloyloxygroup:a glycidyl group calculated from the area ratio of H-NMR was 97:3.

<Synthesis of Resin A2-5>

Resin A2-5 was synthesized in the same manner as in Synthesis Example ofResin A2-6, except that the additive amount of acrylic acid was changedto 26.0 g. The resulting resin A2-5 had a mass-average molecular weightof=14500 and a dispersivity of 2.1. The molar ratio of an acryloyloxygroup:a glycidyl group calculated from the area ratio of H-NMR was90:10.

<Synthesis of Resin A2-7>

Resin A2-7 was synthesized in the same manner as in Synthesis Example ofResin A2-6, except that the additive amount of acrylic acid was changedto 14.4 g. The resulting resin A2-7 had a mass-average molecular weightof 12500 and a dispersivity of 2.0. The molar ratio of an acryloyloxygroup:a glycidyl group calculated from the area ratio of H-NMR was50:50.

<Synthesis of Resin A2-8>

Resin A2-8 was synthesized in the same manner as in Synthesis Example ofResin A2-6, except that the additive amount of V-601 was changed to 7.4g. The resulting resin A2-8 had a mass-average molecular weight of 7200and a dispersivity of 1.8. The molar ratio of an acryloyloxy group:aglycidyl group calculated from the area ratio of H-NMR was 80:20.

<Synthesis of Resin A2-9>

Resin A2-9 was synthesized in the same manner as in Synthesis Example ofResin A2-6, except that the additive amount of V-601 was changed to 2.3g. The resulting resin A2-9 had a mass-average molecular weight of 31200and a dispersivity of 2.5. The molar ratio of an acryloyloxy group:aglycidyl group calculated from the area ratio of H-NMR was 80:20.

<Synthesis of Resin A2-10>

PGMEA (100 g) as a solvent was placed in a flask, and the temperaturewas raised to 90° C. under a nitrogen atmosphere. To the solution wasadded dropwise over 2 hours a mixture of GMA (45.5 g),2-hydroxyethylmethacrylate (HEMA, manufactured by Wako Pure ChemicalIndustries, Ltd.) (10.4 g), V-601 (5.2 g) and PGMEA (50 g). Aftercompletion of the dropwise addition, further stirring was carried out at90° C. for 4 hours to obtain a GMA/HEMA copolymer.

To a solution of the GMA/HEMA copolymer were added AA (17.3 g), TBAB(2.1 g) and 4-HO-TEMPO (50 mg), followed by reaction at 90° C. for 10hours. The resulting resin A2-10 had a mass-average molecular weight of8900 and a dispersivity of 1.9. The molar ratio of an acryloyloxygroup:a glycidyl group:a hydroxyethyl group calculated from the arearatio of H-NMR was 60:20:20.

<Synthesis of Resin A2-11>

PGMEA (100 g) as a solvent was placed in a flask, and the temperaturewas raised to 90° C. under a nitrogen atmosphere. To the solution wasadded dropwise over 2 hours a mixture of3-ethyl-3-oxetanylmethylmethacrylate (OXE-30, manufactured by OSAKAORGANIC CHEMICAL INDUSTRY LTD.) (29.5 g), HEMA (31.2 g), V-601 (4.6 g)and PGMEA (50 g). After completion of the dropwise addition, furtherstirring was carried out at 90° C. for 4 hours to obtain an OXE-30/HEMAcopolymer.

To a solution of the OXE-30/HEMA copolymer were added2-methacryloyloxyethylisocyanate (MOI, manufactured by Showa Denko K.K)(31.0 g) and dibutyltin dilaurate (0.04 g), followed by reaction at 60°C. for 24 hours to obtain a PGMEA solution of Resin A2-11. The resultingresin A2-11 had a mass-average molecular weight of 15500 and adispersivity of 2.2. The molar ratio of a methacrylate group:an oxetanylgroup:a hydroxyethyl group calculated from the area ratio of H-NMR was50:40:10.

Structures of resins are shown below. x, y, and z represent the molarratio of each repeating unit. In the following formulae, Me represents amethyl group.

TABLE 1 Mass- average molecular Resin x:y weight A-1 A-2 A-3 A-4 A-5

90:10 70:30 50:50 30:70 10:90 20300 17800 15100 13500 12000 A-6

50:50 16300 A-7

50:50 16500 A-8

50:50 19700 A-9

50:50 21200  A-10

50:50 14600

TABLE 2 Mass- average molecular Resin x:y:z weight A2-1

90:10  1500 A2-2

80:20  2800 A2-3

80:20  8000 A2-4 A2-5 A2-6 A2-7 A2-8 A2-9

97:3  90:10 80:20 50:50 80:20 80:20 14900 14500 14000 12500  7200 31200 A2-10

60:20:20  8900

TABLE 3 Mass- average molecular Resin x:y:z weight A2-11

50:40:10 15500

TABLE 4 Mass-average Comparative resin, crosslinking agent molecularweight X-1

4000 average m + n = 11, average n/(m + n) = 0.5 NK Oligo EA-7440manufactured by Shin-Nakamura Chemical Co., Ltd. X-2

3500 average n = 11 NK Oligo EA-7420 manufactured by Shin-NakamuraChemical Co., Ltd. X-3

1080 Poly[(o-cresylglycidylether)-co-formaldehyde] (manufactured bySigma-Aldrich Co., LLC) Y-1

 390 Hexamethoxymethylmelamine (manufactured by Cytec Industries Inc.,CYMEL 303 ULF)

TABLE 5 Mass-average Comparative resin x:y molecular weight X-4

50:50 13400 X-5

50:50 18600

<Preparation of Resin Composition for Underlayer Film Formation>

The resin composition components were dissolved at the solid contentratio (mass ratio) shown in Tables below and to a total solid content of0.2 mass % in PGMEA. The solution was filtered through a 0.1 μmpolytetrafluoroethylene (PTFE) filter to obtain a resin composition forunderlayer film formation.

TABLE 6 Composition of resin composition for underlayer film formationV1 V2 V3 V4 V5 V6 V7 V8 V9 V10 V11 V12 V13 V14 V15 Resin A-3 90 90 90 9099 99.9 89 89 A-9 82 86 75 A-1 95 70 A-5 95 A2-7 90 Surfactant W1 10 10.1 18 14 10 10 30 25 W2 10 10 W3 10 W4 10 5 5 Acid, and C-1 1 thermalC-2 1 acid generator

TABLE 7 Comparative resin composition for underlayer film formation R1R2 R3 R4 R5 R6 R7 R8 Comparative X-1 79 99 resin X-2 79 99 X-3 99 X-4100 X-5 100 99 Crosslinking Y-1 20 20 agent Acid, and C-1 1 1 1 1 1 1thermal acid generator

<Nonionic Surfactant>

W-1: CAPSTONE FS-3100 (manufactured by E.I. du Pont de Nemours andCompany Co., Ltd.)

W-2: POLYFOX PF-6320 (manufactured by OMNOVA Solutions Inc.)

W-3: DSN-403N (manufactured by Daikin Industries, Ltd.)

W-4: FTERGENT FT212M (manufactured by Neos Company Limited Co., Ltd.)

<Acid, and Thermal Acid Generator>

C-1: p-Toluenesulfonic acid (manufacturer: Wako Pure ChemicalIndustries, Ltd.)

C-2: Isopropyl-p-toluene sulfonate (manufacturer: Wako Pure ChemicalIndustries, Ltd.)

<Preparation of Photocurable Composition for Imprints>

A polymerizable compound, a photopolymerization initiator, and additivesshown in the following table were mixed. Further,4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radicals(manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerizationinhibitor were added to 200 ppm (0.02 mass %) relative to the monomer.This was filtered through a 0.1 μm PTFE filter to prepare a photocurablecomposition for imprints. In the table, individual components are givenin terms of mass ratio.

TABLE 8 Mass Available from ratio M-1 VISCOAT #192 48 (manufactured byOsaka Organic Chemical Industry, Ltd.) M-2 Synthesized from α, 48α′-dichloro-m-xylene and acrylic acid M-3 R-1620  2 (manufactured byDaikin Industries, Ltd.) Photopolymerization Irgacure 907  2 initiator(manufactured by BASF SE)

M-1

M-2

M-3

<Formation of Underlayer Film>

A resin composition for underlayer film formation was spin-coated on thesurface of a SOG (Spin On Glass) film (surface energy: 55 mJ/m²) formedon a silicon wafer, and heated on a hot plate at 100° C. for 1 minute todry a solvent. Further, baking (heating) was carried out on a hot plateat 180° C. or 150° C. for 5 minutes, thereby forming an underlayer filmon the surface of a silicon wafer having an SOG film. The film thicknessof the underlayer film after curing was 5 nm.

Contact angles of the resulting underlayer film with respect to water,diiodomethane, and a photocurable composition for imprints (resist) weremeasured by the method described in the present specification.Specifically, the contact angle of the film was measured by a method oflanding measurement solvents such as water, diiodomethane and aphotocurable composition for imprints in a state of 2 μL droplets on thesubstrate surface with formation of an underlayer film which is ameasurement target, using a contact angle meter DM-701 (manufactured byKyowa Interface Science Co., Ltd) under the conditions of 25° C. and 45%RH, and then calculating a contact angle from droplet shapes after 500ms following landing.

(Evaluation 1)

<Evaluation of Surface Flatness of Underlayer Film>

Using an atomic force microscope (AFM, Dimension Icon manufactured byBruker AXS Ltd.), a 10 μm square of the underlayer film obtained abovewas measured at a 1024×1024 pitch for surface roughness data, and thearithmetic average surface roughness (Ra) was calculated. The resultsare shown in the following Table. Smaller Ra indicates better surfaceflatness.

A: Ra<0.3 nm

B: 0.3 nm≤Ra<0.5 nm

C: 0.5 nm≤Ra<1.0 nm

D: 1.0 nm≤Ra

<Evaluation of Adhesiveness>

The resin composition for underlayer film formation was spin-coated overthe surface of a quartz wafer, and heated on a hot plate at 100° C. for1 minute to thereby dry up the solvent. The resin composition forunderlayer film formation was further heated on a hot plate at 180° C.for 5 minutes to thereby form an underlayer film over the quartz wafersurface. The film thickness of the underlayer film after curing was 5nm.

Over the surface of the underlayer film formed on the above-mentionedsilicon wafer having an SOG film, the photocurable composition forimprints conditioned at 25° C. was ejected and coated in a circularpattern having a diameter of 40 mm using an inkjet printer “DMP-2831”manufactured by FUJIFILM Dimatix, Inc., at a liquid droplet volume pernozzle of 1 pl, so as to align droplets according to an approximately100 μm-pitch square array on the underlayer film, thereby forming apatterning layer. The quartz wafer was then pressed against the siliconwafer so as to bring the underlayer film of the quartz wafer intocontact with the patterning layer, followed by exposure to light fromthe quartz wafer side using a high pressure mercury lamp at anirradiation dose of 300 mJ/cm². After the exposure, the quartz wafer wasseparated, and the releasing force at that time was measured accordingto the method described in the Comparative Examples in paragraphs “0102”to “0107” of JP2011-206977A. More specifically, the measurement wascarried out according to separation steps 1 to 6 and 16 to 18 in FIG. 5of this publication.

The releasing force corresponds to the adhesive force F (unit: N)between the silicon wafer and the photocurable composition for imprints,in which the larger the adhesive force F, the better the adhesiveness ofthe underlayer film.

S: F≥45 N

A: 45 N>F≥40 N

B: 40 N>F≥30 N

C: 30 N>F≥20 N

D: 20 N>F

<Evaluation of Separation Failure>

Over the surface of the underlayer film formed on the above-mentionedsilicon wafer having an SOG film, the photocurable composition forimprints conditioned at 25° C. was ejected and coated using an inkjetprinter “DMP-2831” manufactured by FUJIFILM Dimatix, Inc., at a liquiddroplet volume per nozzle of 1 pl, so as to align droplets according toan approximately 115 μm-pitch square array on the underlayer film,thereby forming a patterning layer. A quartz mold (rectangularline/space pattern (1/1), line width=60 nm, groove depth=100 nm, andline edge roughness=3.5 nm) was then pressed against the patterninglayer, so as to fill the patterning layer (photocurable composition forimprints) into the mold. This was followed by exposure to light from themold side using a high pressure mercury lamp at an irradiation dose of300 mJ/cm², and thereafter the mold was separated. The pattern was thustransferred to the patterning layer.

When the cross-section of the prepared pattern sample was observed undera scanning electron microscope S4800 (manufactured by HitachiHigh-Technologies Corporation), a 10-point average thickness of theresidual film layer was 25 nm.

The pattern thus transferred to the patterning layer was observed underan optical microscope (STM6-LM, manufactured by Olympus Corporation) toevaluate separation failure on the patterning layer.

A: No separation failure observed over total pattern area.

B: Separation failure observed in area less than 5% of total patternarea.

C: Separation failure observed in area 5% or more and less than 50% oftotal pattern area.

D: Separation failure observed in area 50% or more of total pattern area

(Evaluation 2)

Evaluation sample 2 was prepared in the same manner as in Evaluation 1,except that, in the evaluation of separation failure carried out inEvaluation 1, a mold having a rectangular line/space pattern (1/1), aline width=40 nm, a groove depth=105 nm and a line edge roughness=3.2 nmwas used as the quartz mold, and the photocurable composition forimprints conditioned at 25° C. was ejected and coated using an inkjetprinter DMP-2831 (manufactured by FUJIFILM Dimatix, Inc.) at a liquiddroplet volume per nozzle of 1 pl, so as to align droplets according toan approximately 120 μm-pitch square array on the underlayer film.

When the cross-section of the prepared pattern sample was observed undera scanning electron microscope S4800 (manufactured by HitachiHigh-Technologies Corporation), a 10-point average thickness of theresidual film layer was about 15 nm.

<Separation Failure>

The pattern sample obtained by Evaluation 2 was evaluated according tothe same standards as in the evaluation method of separation failuredescribed Evaluation 1.

<Residual Film Thickness Distribution>

To verify the position dependence of the residual film thickness of theresidual film layer between the pattern bottom of the pattern sampleobtained by Evaluation 2 and the substrate, the residual film thicknessof 16 points at a 5 mm grid spacing in the cross-section of the samplewas measured by a scanning reflection electron microscope (S4800,manufactured by Hitachi High-Technologies Corporation). Then, thedifference Δd between the maximum value and the minimum value wasdetermined and evaluated as follows.

A: Δd≥5 nm

B: 10 nm>Δd≥5 nm

C: 15 nm>Δd≥10 nm

D: Δd≥15 nm

<Post-Processing Line Width Distribution>

The pattern sample obtained by Evaluation 2 was subjected to an etchingtreatment for a period of time capable of forming a groove patternhaving a 80 nm depth on a substrate under the conditions of CHF₃/CF₄/ArBIAS 600 W and ICP voltage 100 W 0.3 Pa, using a reactive ion etchingapparatus Centura (manufactured by AMAT Co., Ltd.). For the line widthof the pattern after etching, the line width CD was measured at in-plane16 spots, using a CD-SEM (RS5500, manufactured by HitachiHigh-Technologies Corporation). The difference ΔCD between the maximumvalue and the minimum value was determined from the obtained CD value,and was evaluated as follows.

A: ΔCD≤4 nm

B: 6 nm≤ΔCD<4 nm

C: 10 nm≤ΔCD<6 nm

D: ΔCD<10 nm

TABLE 9 Evaluation 2 Resin Baking Residual Post- composition temper-Evaluation 1 film processing Contact for underlayer ature Contact angle(°) Surface Adhe- Separation thickness Separation line width angle (°)film formation (° C.) Water Diiodomethane flatness siveness failuredistribution failure distribution Resist Example 1 V1 180 69 51 A S A AA A 28 Example 2 V2 180 68 50 A S A A A A 27 Example 3 V3 180 72 54 A SA A A A 31 Example 4 V4 180 62 43 A S A A A A 21 Example 5 V5 180 56 35A S A A B A 15 Example 6 V6 180 52 32 A S A A B A 11 Example 7 V7 180 7762 B A A B A B 36 Example 8 V8 180 74 58 A A A A A A 33 Example 9 V9 15068 51 A S A A A A 27 Example 10 V10 150 67 48 A S A A A A 26 Example 11V11 180 64 46 A S A A A A 22 Example 12 V12 180 65 46 A S A A A A 23Example 13 V13 180 68 49 A S A A A A 27 Example 14 V14 180 83 69 B A B BB B 44 Example 15 V15 180 79 65 B A A B A B 40 Comparative R1 180 38 18D A B C B C <3 Example 1 Comparative R2 180 39 19 D B C C C C <3 Example2 Comparative R3 180 38 19 C C C C C C <3 Example 3 Comparative R4 18039 18 B D D C D C <3 Example 4 Comparative R5 180 42 21 C D D D D D <3Example 5 Comparative R6 180 43 23 A C C B C B <3 Example 6 ComparativeR7 180 43 22 B D D B D B <3 Example 7 Comparative R1 150 38 20 B C C B CB <3 Example 8 Comparative R8 150 43 23 C C C C C C <3 Example 9

As can be seen from the above results, the resin composition forunderlayer film formation according to the present invention exhibitedgood residual film thickness distribution and post-processing line widthdistribution. Furthermore, it became possible to further improveseparation failure in imprinting. Further, from the results ofseparation failure of Evaluation 2, it was found that the line width ofa mold pattern is narrowed and therefore the releasing is achievedwithout problems even with a pattern where an aspect ratio is improved,and it was found that applicability to a pattern having a finer linewidth is increased, and consequently it is possible to provide acomposition for forming an underlayer film capable of further improvingproductivity, for example, in a case of being applied to manufacture ofsemiconductor chips.

On the other hand, the resin compositions for underlayer film formationof Comparative Examples exhibited large post-processing line widthdistribution due to large residual film thickness distribution.

The same results were obtained even when, in individual Examples, thelight source for curing the curable composition was changed from thehigh pressure mercury lamp to an LED, metal halide lamp or excimer lamp.

The same tendencies were confirmed even when, in individual Examples,the substrate used for measurement of adhesive force was changed fromthe silicon wafer coated with spin-on-glass (SOG) to a silicon wafer orquartz wafer.

The same effects were obtained as in Examples 1 to 4, even when, inExamples 1 to 4, the resin in the resin composition for underlayer filmformation was changed from Resin A-3 to the same mass of Resins A-1,A-2, A-4 to A-11, and A2-1 to A2-11.

EXPLANATION OF REFERENCES

-   -   1: base material    -   2: underlayer film    -   3: imprint layer    -   4: mold

What is claimed is:
 1. A resin composition for underlayer filmformation, comprising: a resin having a group represented by GeneralFormula (A) and at least one group selected from a group represented byGeneral Formula (B), an oxiranyl group and an oxetanyl group; a nonionicsurfactant; and a solvent:

in General Formulae (A) and (B), the wavy line represents a positionconnected to the main chain or side chain of the resin, R^(a1)represents a hydrogen atom or a methyl group, and R^(b1) and R^(b2) eachindependently represent a group selected from an unsubstituted linear orbranched alkyl group having 1 to 20 carbon atoms and an unsubstitutedcycloalkyl group having 3 to 20 carbon atoms, R^(b3) represents a groupselected from an unsubstituted linear or branched alkyl group having 2to 20 carbon atoms and an unsubstituted cycloalkyl group having 3 to 20carbon atoms, and R^(b2) and R^(b3) may be bonded to each other to forma ring.
 2. The resin composition for underlayer film formation accordingto claim 1, comprising 0.01 to 25 parts by mass of the nonionicsurfactant with respect to 100 parts by mass of the resin.
 3. The resincomposition for underlayer film formation according to claim 1, wherein,in General Formula (B), at least one of R^(b1), R^(b2), and R^(b3) is acycloalkyl group having 3 to 20 carbon atoms, or R^(b2) and R^(b3) arebonded to each other to form a ring.
 4. The resin composition forunderlayer film formation according to claim 1, wherein the resin has atleast one repeating unit selected from the following General Formulae(II) to (IV):

in General Formulae (II) to (IV), R²¹ and R³¹ each independentlyrepresent a hydrogen atom or a methyl group, R²², R²³, R³², R³³, R⁴²,and R⁴³ each independently represent a group selected from anunsubstituted linear or branched alkyl group having 1 to 20 carbon atomsand an unsubstituted cycloalkyl group having 3 to 20 carbon atoms, R²⁴,R³⁴, and R⁴⁴ each independently represent a group selected from anunsubstituted linear or branched alkyl group having 2 to 20 carbon atomsand an unsubstituted cycloalkyl group having 3 to 20 carbon atoms, R²³and R²⁴, R³³ and R³⁴, and R⁴³ and R⁴⁴ each may be bonded to each otherto form a ring, and L³ and L⁴ each independently represent a divalentlinking group.
 5. The resin composition for underlayer film formationaccording to claim 1, wherein the resin has a repeating unit representedby General Formula (I) and at least one of a repeating unit representedby General Formula (II) and a repeating unit represented by GeneralFormula (III), and has a mass-average molecular weight of 5,000 to50,000:

in General Formulae (I) to (III), R¹¹, R¹², R²¹, and R³¹ eachindependently represent a hydrogen atom or a methyl group, R²², R²³, R³²and R³³ each independently represent a group selected from anunsubstituted linear or branched alkyl group having 1 to 20 carbon atomsand an unsubstituted cycloalkyl group having 3 to 20 carbon atoms, R²⁴and R³⁴ each independently represent a group selected from anunsubstituted linear or branched alkyl group having 2 to 20 carbon atomsand an unsubstituted cycloalkyl group having 3 to 20 carbon atoms, andR²³ and R²⁴, and R³³ and R³⁴ each may be bonded to each other to form aring, and L¹ and L³ each independently represent a divalent linkinggroup.
 6. The resin composition for underlayer film formation accordingto claim 5, wherein the resin contains a repeating unit selected from arepeating unit where, in General Formula (II), at least one of R²², R²³,and R²⁴ is a cycloalkyl group having 3 to 20 carbon atoms, or R²³ andR²⁴ are bonded to each other to form a ring, and a repeating unit where,in General Formula (III), at least one of R³², R³³, and R³⁴ is acycloalkyl group having 3 to 20 carbon atoms, or R³³ and R³⁴ are bondedto each other to form a ring.
 7. The resin composition for underlayerfilm formation according to claim 5, wherein the resin has a molar ratioof repeating units represented by General Formula (I): a total ofrepeating units represented by General Formula (II) and repeating unitsrepresented by General Formula (III) of 5:95 to 95:5.
 8. The resincomposition for underlayer film formation according to claim 1, whereinthe resin has a repeating unit having a group represented by GeneralFormula (A), and a repeating unit having at least one group selectedfrom an oxiranyl group and an oxetanyl group.
 9. The resin compositionfor underlayer film formation according to claim 8, wherein the resinhas a molar ratio of the repeating unit having a group represented byGeneral Formula (A): the repeating unit having at least one groupselected from an oxiranyl group and an oxetanyl group of 10:90 to 97:3.10. The resin composition for underlayer film formation according toclaim 8, wherein the resin has at least one repeating unit selected fromthe following General Formulae (1) to (3) and at least one repeatingunit selected from the following General Formulae (4) to (6):

in General Formulae (1) to (6), R¹¹¹, R¹¹², R¹²¹, R¹²², R¹³¹, R¹³²,R¹⁴¹, R¹⁵¹ and R¹⁶¹ each independently represent a hydrogen atom or amethyl group, L¹¹⁰, L¹²⁰, L¹³⁰, L¹⁴⁰, L¹⁵⁰ and L¹⁶⁰ each independentlyrepresent a single bond or a divalent linking group, and T representsany one of the groups represented by General Formulae (T-1), (T-2) and(T-3);

in General Formulae (T-1) to (T-3), R^(T1) and R^(T3) each independentlyrepresent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms,p represents 0 or 1, q represents 0 or 1, n represents an integer of 0to 2, and a wavy line represents a position connected to L¹⁴⁰, L¹⁵⁰ orL¹⁶⁰.
 11. The resin composition for underlayer film formation accordingto claim 10, wherein T is a group represented by General Formula (T-1).12. The resin composition for underlayer film formation according toclaim 1, wherein the solvent is propylene glycol monomethyl etheracetate.
 13. The resin composition for underlayer film formationaccording to claim 1, further comprising at least one of an acid and athermal acid generator.
 14. The resin composition for underlayer filmformation according to claim 1, wherein the content of the solvent is 95to 99.9 mass %.
 15. The resin composition for underlayer film formationaccording to claim 1, wherein the contact angle of the film formed ofthe resin composition for underlayer film formation with respect towater is 50° or more, and the contact angle of the film with respect todiiodomethane is 30° or more.
 16. The resin composition for underlayerfilm formation according to claim 1, which is used for the formation ofan underlayer film for imprints.
 17. A layered product having anunderlayer film obtained by curing the resin composition for underlayerfilm formation according to of claim 1 on the surface of a basematerial.
 18. A method for forming a pattern, comprising: applying theresin composition for underlayer film formation according to claim 1onto the surface of a base material in the form of layer; heating theapplied resin composition for underlayer film formation to form anunderlayer film; applying a photocurable composition onto a surface ofthe underlayer film in the form of layer; pressing a mold having apattern on the photocurable composition; curing the photocurablecomposition by photoirradiation in a state of the mold being pressed;and separating the mold.
 19. The method for forming a pattern accordingto claim 18, wherein the heating temperature is 120° C. to 250° C. andthe heating time is 30 seconds to 10 minutes, in the step of forming anunderlayer film.
 20. An imprint forming kit having the resin compositionfor underlayer film formation according to claim 1 and a photocurablecomposition.
 21. The imprint forming kit according to claim 20, whereinthe contact angle of the film formed of the resin composition forunderlayer film formation with respect to the photocurable compositionis 10° or more.
 22. A process for producing a device, comprising themethod for forming a pattern according to claim 18.